373 lines
13 KiB
JavaScript
373 lines
13 KiB
JavaScript
/*
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* onScan.js - scan-events for hardware barcodes scanners in javascript
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*/
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var onScan = {
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attachTo: function(oDomElement, oOptions) {
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if (oDomElement.scannerDetectionData != undefined) {
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throw new Error(
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"onScan.js is already initialized for DOM element " + oDomElement
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);
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}
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var oDefaults = {
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onScan: function(sScanned, iQty) {}, // Callback after detection of a successfull scanning: function(){sScancode, iCount)}()
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onScanError: function(oDebug) {}, // Callback after detection of a unsuccessfull scanning (scanned string in parameter)
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onKeyProcess: function(sChar, oEvent) {}, // Callback after receiving and processing a char (scanned char in parameter)
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onKeyDetect: function(iKeyCode, oEvent) {}, // Callback after detecting a keypress (key char in parameter) - in contrast to onKeyProcess, this fires for non-character keys like tab, arrows, etc. too!
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onPaste: function(sPasted, oEvent) {}, // Callback after receiving a value on paste, no matter if it is a valid code or not
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keyCodeMapper: function(oEvent) {
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return String.fromCharCode(oEvent.which);
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}, // Custom function to decode a keypress event into a character. Must return decoded character or NULL if the given event should not be processed.
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onScanButtonLongPress: function() {}, // Callback after detection of a successfull scan while the scan button was pressed and held down
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scanButtonKeyCode: false, // Key code of the scanner hardware button (if the scanner button a acts as a key itself)
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scanButtonLongPressTime: 500, // How long (ms) the hardware button should be pressed, until a callback gets executed
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timeBeforeScanTest: 100, // Wait duration (ms) after keypress event to check if scanning is finished
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avgTimeByChar: 30, // Average time (ms) between 2 chars. Used to do difference between keyboard typing and scanning
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minLength: 6, // Minimum length for a scanning
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suffixKeyCodes: [9, 13], // Chars to remove and means end of scanning
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prefixKeyCodes: [], // Chars to remove and means start of scanning
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ignoreIfFocusOn: false, // do not handle scans if the currently focused element matches this selector or object
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stopPropagation: false, // Stop immediate propagation on keypress event
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preventDefault: false, // Prevent default action on keypress event
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reactToKeypress: true, // look for scan input in keyboard events
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reactToPaste: false, // look for scan input in paste events
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singleScanQty: 1 // Quantity of Items put out to onScan in a single scan
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};
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oOptions = this._mergeOptions(oDefaults, oOptions);
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// initializing options and variables on DomElement
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oDomElement.scannerDetectionData = {
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options: oOptions,
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vars: {
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firstCharTime: 0,
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lastCharTime: 0,
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stringWriting: "",
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callIsScanner: false,
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testTimer: false,
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longPressTimeStart: 0,
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longPressed: false
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}
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};
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// initializing handlers (based on settings)
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if (oOptions.reactToPaste === true) {
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oDomElement.addEventListener("paste", this._handlePaste);
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}
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if (oOptions.scanButtonKeyCode !== false) {
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oDomElement.addEventListener("keyup", this._handleKeyUp);
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}
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if (
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oOptions.reactToKeypress === true ||
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oOptions.scanButtonKeyCode !== false
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) {
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oDomElement.addEventListener("keypress", this._handleKeyPress);
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}
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},
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detachFrom: function(oDomElement) {
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// detaching all used events
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if (oDomElement.scannerDetectionData.options.reactToPaste) {
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oDomElement.removeEventListener("paste", this._handlePaste);
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}
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if (oDomElement.scannerDetectionData.options.scanButtonKeyCode !== false) {
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oDomElement.removeEventListener("keyup", this._handleKeyUp);
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}
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oDomElement.removeEventListener("keypress", this._handleKeyPress);
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// clearing data off DomElement
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oDomElement.scannerDetectionData = undefined;
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},
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getOptions: function(oDomElement) {
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return oDomElement.scannerDetectionData.options;
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},
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setOptions: function(oDomElement, oOptions) {
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// check if some handlers need to be changed based on possible option changes
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switch (oDomElement.scannerDetectionData.options.reactToPaste) {
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case true:
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if (oOptions.reactToPaste === false) {
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oDomElement.removeEventListener("paste", this._handlePaste);
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}
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break;
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case false:
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if (oOptions.reactToPaste === true) {
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oDomElement.addEventListener("paste", this._handlePaste);
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}
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break;
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}
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switch (oDomElement.scannerDetectionData.options.scanButtonKeyCode) {
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case false:
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if (oOptions.scanButtonKeyCode !== false) {
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oDomElement.addEventListener("keyup", this._handleKeyUp);
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}
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break;
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default:
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if (oOptions.scanButtonKeyCode === false) {
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oDomElement.removeEventListener("keyup", this._handleKeyUp);
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}
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break;
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}
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// merge old and new options
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oDomElement.scannerDetectionData.options = this._mergeOptions(
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oDomElement.scannerDetectionData.options,
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oOptions
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);
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// reinitiallize
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this._reinitialize(oDomElement);
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},
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simulate: function(oDomElement, sTestString) {
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var oVars = oDomElement["scannerDetectionData"].vars;
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oVars.firstCharTime = 0;
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oVars.lastCharTime = 0;
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oVars.stringWriting = sTestString;
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this._validateScanCode(oDomElement);
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return this;
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},
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_reinitialize: function(oDomElement) {
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var oVars = oDomElement["scannerDetectionData"].vars;
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oVars.firstCharTime = 0;
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oVars.stringWriting = "";
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},
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_isFocusOnIgnoredElement: function(oDomElement) {
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ignoreSelectors =
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oDomElement["scannerDetectionData"].options.ignoreIfFocusOn;
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if (!ignoreSelectors) {
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return false;
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}
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var oFocused = document.activeElement;
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// checks if ignored element is an array, and if so it checks if one of the elements of it is an active one
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if (Array.isArray(ignoreSelectors)) {
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for (var i = 0; i < ignoreSelectors.length; i++) {
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if (oFocused.matches(ignoreSelectors[i]) === true) {
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return true;
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}
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}
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// if the option consists of an single element, it only checks this one
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} else if (oFocused.matches(ignoreSelectors)) {
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return true;
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}
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// if the active element is not listed in the ignoreIfFocusOn option, return false
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return false;
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},
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_validateScanCode: function(oDomElement) {
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var oScannerData = oDomElement["scannerDetectionData"];
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var oOptions = oScannerData.options;
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var iSingleScanQty = oScannerData.options.singleScanQty;
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var sScanCode = oScannerData.vars.stringWriting;
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var iFirstCharTime = oScannerData.vars.firstCharTime;
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var iLastCharTime = oScannerData.vars.lastCharTime;
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switch (true) {
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// detect codes that are too short
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case sScanCode.length < oOptions.minLength:
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var oScanError = {
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message: "Receieved code is shorter then minimal length"
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};
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break;
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// detect codes that were entered too slow
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case iLastCharTime - iFirstCharTime >
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sScanCode.length * oOptions.avgTimeByChar:
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var oScanError = {
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message: "Receieved code was not entered in time"
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};
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break;
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// if a code was not filtered out earlier it is valid
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default:
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oOptions.onScan.call(oDomElement, sScanCode, iSingleScanQty);
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var oEvent = new CustomEvent("scan", {
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detail: {
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scanCode: sScanCode,
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qty: iSingleScanQty
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}
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});
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oDomElement.dispatchEvent(oEvent);
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onScan._reinitialize(oDomElement);
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return true;
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}
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// If an error occurred (otherwise the method would return earlier) create an object for errordetection
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oScanError.scanCode = sScanCode;
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oScanError.scanDuration = iLastCharTime - iFirstCharTime;
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oScanError.avgTimeByChar = oOptions.avgTimeByChar;
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oScanError.minLength = oOptions.minLength;
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oOptions.onScanError.call(oDomElement, oScanError);
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var oEvent = new CustomEvent("scanError", oScanError);
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oDomElement.dispatchEvent(oEvent);
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onScan._reinitialize(oDomElement);
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return false;
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},
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_mergeOptions: function(oDefaults, oOptions) {
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var oExtended = {};
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var prop;
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for (prop in oDefaults) {
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if (Object.prototype.hasOwnProperty.call(oDefaults, prop)) {
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oExtended[prop] = oDefaults[prop];
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}
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}
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for (prop in oOptions) {
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if (Object.prototype.hasOwnProperty.call(oOptions, prop)) {
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oExtended[prop] = oOptions[prop];
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}
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}
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return oExtended;
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},
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_getNormalizedKeyNum: function(e) {
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var iKeyCode;
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if (window.event) {
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// IE
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iKeyCode = e.keyCode;
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} else if (e.which) {
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// Netscape/Firefox/Opera
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iKeyCode = e.which;
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}
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return iKeyCode;
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},
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_handleKeyPress: function(e) {
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// overwrite the which value of the event with keycode for cross platform compatibility
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e.which = onScan._getNormalizedKeyNum(e);
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var iKeyCode = e.which;
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var oOptions = this["scannerDetectionData"].options;
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var oVars = this["scannerDetectionData"].vars;
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oOptions.onKeyDetect.call(this, e.which, e);
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if (onScan._isFocusOnIgnoredElement(this)) {
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return;
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}
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// If it's just the button of the scanner, ignore it and wait for the real input
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if (
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oOptions.scanButtonKeyCode !== false &&
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iKeyCode == oOptions.scanButtonKeyCode
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) {
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// if the button was first pressed, start a timeout for the callback, which gets interrupted if the scanbutton gets released
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if (!oVars.longPressed) {
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oVars.longPressTimer = setTimeout(
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oOptions.onScanButtonLongPress,
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oOptions.scanButtonLongPressTime,
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this
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);
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oVars.longPressed = true;
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}
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return;
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}
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if (oOptions.stopPropagation) {
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e.stopImmediatePropagation();
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}
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if (oOptions.preventDefault) {
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e.preventDefault();
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}
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switch (true) {
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// If it's not the first character and we encounter a terminating character, trigger scan process
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case oVars.firstCharTime &&
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oOptions.suffixKeyCodes.indexOf(iKeyCode) !== -1:
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e.preventDefault();
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e.stopImmediatePropagation();
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this["scannerDetectionData"].vars.callIsScanner = true;
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break;
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// If it's the first character and we encountered one of the starting characters, don't process the scan
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case !oVars.firstCharTime &&
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oOptions.prefixKeyCodes.indexOf(iKeyCode) !== -1:
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e.preventDefault();
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e.stopImmediatePropagation();
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oVars.callIsScanner = false;
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break;
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// Otherwise, just add the character to the scan string we're building
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default:
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var character = oOptions.keyCodeMapper.call(this, e);
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if (character === null) {
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return;
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}
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oVars.stringWriting += character;
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oVars.callIsScanner = false;
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break;
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}
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if (!oVars.firstCharTime) {
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oVars.firstCharTime = Date.now();
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}
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oVars.lastCharTime = Date.now();
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if (oVars.testTimer) {
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clearTimeout(oVars.testTimer);
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}
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if (oVars.callIsScanner) {
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onScan._validateScanCode(this);
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oVars.testTimer = false;
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} else {
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oVars.testTimer = setTimeout(
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onScan._validateScanCode,
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oOptions.timeBeforeScanTest,
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this
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);
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}
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oOptions.onKeyProcess.call(this, character, e);
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},
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_handlePaste: function(e) {
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// if the focus is on an ignored element, abort
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if (onScan._isFocusOnIgnoredElement(this)) {
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return;
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}
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e.preventDefault();
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var sPasteString = (event.clipboardData || window.clipboardData).getData(
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"text"
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);
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this.scannerDetectionData.options.onPaste.call(this, sPasteString, event);
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var oVars = this.scannerDetectionData.vars;
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oVars.firstCharTime = 0;
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oVars.lastCharTime = 0;
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oVars.stringWriting = sPasteString;
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// validate the string
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onScan._validateScanCode(this);
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},
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_handleKeyUp: function(e) {
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// if the focus is on an ignored element, abort
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if (onScan._isFocusOnIgnoredElement(this)) {
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return;
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}
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var iKeyCode = onScan._getNormalizedKeyNum(e);
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// if hardware key is not being pressed anymore stop the timeout and reset
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if (iKeyCode == this.scannerDetectionData.options.scanButtonKeyCode) {
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clearTimeout(this.scannerDetectionData.vars.longPressTimer);
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this.scannerDetectionData.vars.longPressed = false;
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}
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}
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};
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