Develop Reference

How do i read only value attr?

I want make value attribute to read-only and i do these code but not work ??
Need help ?
const obj = {
name: "karl"
}
const origName = obj.name;
Object.defineProperty(obj, 'name', {
enumerable: false,
configurable: false,
get() {
return origName + 2;
}
});

You must add "writebale" key;
Like this;
Object.defineProperty(obj, "name", {
value: "karl",
writable: false
});

You could instead use the writable property of the property descriptor, which prevents the need for a get accessor:
Object.defineProperty(obj, 'name', {
value: "karl",
writable: false
get() {
return origName + 2;
}
});

Iterate till the end of the nested objects in javascript

I have a nested object like this :
let obj = {
_id: {},
person: {
$search: {
lname: true
},
_id: {},
fname: {},
something:{
$search: {
fname: true
},
}
},
code: {},
$search: {
mname: true
},
vnvEmpName: {}
}
I have to retrieve all the keys inside the $search key, even if the object contains multiple occurences of $search it should return all the keys inside it which is :
lname
fname
mname
I tried this :
function search(obj, id) {
var result = "";
// iterate the object using for..in
for (var keys in obj) {
// check if the object has any property by that name
if (obj.hasOwnProperty(keys) && typeof obj[keys] === 'object') {
// if the key is not undefined get it's value
if (obj[keys][id] !== undefined) {
result = (obj[keys][id])
} else {
// else again call the same function using the new obj value
console.log("reahced")
search(obj[keys], id)
}
}
}
return result;
}
console.log(search(obj, '$search'))
But I am getting only the key(lname) which is under the first instance of the $search. Please help me out to iterate it till the end.

You can try this
let obj = {
_id: {},
person: {
$search : {
lname: true
},
_id: {},
fname: 'test',
something:{
$search: {
fname: true
},
}
},
code: {},
$search: {
mname: true
},
vnvEmpName: {}
}
var result;
function search(obj, id) {
// iterate the object using for..in
for (var key in obj) {
if (obj.hasOwnProperty(key)) {
if (obj[key][id] !== undefined) {
result = (obj[key][id]);
return result;
} else {
// else again call the same function using the new obj value
console.log("reahced")
search(obj[key], id)
}
}
}
return result;
}
console.log(search(obj, 'lname'))

You could check if the key is $search and take that nested key or check the nested objects.
function getSearch(object, key) {
return Object.entries(object).reduce((r, [k, v]) => r.concat(
k === key
? Object.keys(v)[0]
: v && typeof v === 'object'
? getSearch(v, key)
: []
), []);
}
var object = { _id: {}, person: { $search: { lname: true }, _id: {}, fname: {}, something: { $search: { fname: true } } }, code: {}, $search: { mname: true }, vnvEmpName: {} };
console.log(getSearch(object, '$search'));
.as-console-wrapper { max-height: 100% !important; top: 0; }

You can create an iterator function using generators and then use it for your purpose. Here is an example code:
let obj = { _id: {}, person: { $search: { lname: true }, _id: {}, fname: {}, something: { $search: { fname: true } } }, code: {}, $search: { mname: true }, vnvEmpName: {} };
//iterator function
function* iterate(obj, stack='') {
for (let property in obj) {
if (obj.hasOwnProperty(property)) {
if (typeof obj[property] == "object") {
yield *iterate(obj[property], stack + '.' + property);
} else {
yield [stack, property, obj[property]];
}
}
}
}
//using iterator function for searching
let searchkey = "$search"
for (let value of iterate(obj)) {
if(value[0].indexOf(searchkey) !== -1)
console.log(value);
}
I hope it helps.

get quaggaJS barcode results on input field

I am a newbie to HTML/Javascript Language.
I am trying to implement quaggaJS barcode scanner Using the live-stream into my HTML page. its working fine but what i want is to get the result on input field.
Below is my input field:
<input class="form-control" type="number" name="id" required autofocus>
This is live_w_locator.js file from quaggaJS:
$(function() {
var resultCollector = Quagga.ResultCollector.create({
capture: true,
capacity: 20,
blacklist: [{
code: "WIWV8ETQZ1", format: "code_93"
}, {
code: "EH3C-%GU23RK3", format: "code_93"
}, {
code: "O308SIHQOXN5SA/PJ", format: "code_93"
}, {
code: "DG7Q$TV8JQ/EN", format: "code_93"
}, {
code: "VOFD1DB5A.1F6QU", format: "code_93"
}, {
code: "4SO64P4X8 U4YUU1T-", format: "code_93"
}],
filter: function(codeResult) {
// only store results which match this constraint
// e.g.: codeResult
return true;
}
});
var App = {
init: function() {
var self = this;
Quagga.init(this.state, function(err) {
if (err) {
return self.handleError(err);
}
//Quagga.registerResultCollector(resultCollector);
App.attachListeners();
App.checkCapabilities();
Quagga.start();
});
},
handleError: function(err) {
console.log(err);
},
checkCapabilities: function() {
var track = Quagga.CameraAccess.getActiveTrack();
var capabilities = {};
if (typeof track.getCapabilities === 'function') {
capabilities = track.getCapabilities();
}
this.applySettingsVisibility('zoom', capabilities.zoom);
this.applySettingsVisibility('torch', capabilities.torch);
},
updateOptionsForMediaRange: function(node, range) {
console.log('updateOptionsForMediaRange', node, range);
var NUM_STEPS = 6;
var stepSize = (range.max - range.min) / NUM_STEPS;
var option;
var value;
while (node.firstChild) {
node.removeChild(node.firstChild);
}
for (var i = 0; i <= NUM_STEPS; i++) {
value = range.min + (stepSize * i);
option = document.createElement('option');
option.value = value;
option.innerHTML = value;
node.appendChild(option);
}
},
applySettingsVisibility: function(setting, capability) {
// depending on type of capability
if (typeof capability === 'boolean') {
var node = document.querySelector('input[name="settings_' + setting + '"]');
if (node) {
node.parentNode.style.display = capability ? 'block' : 'none';
}
return;
}
if (window.MediaSettingsRange && capability instanceof window.MediaSettingsRange) {
var node = document.querySelector('select[name="settings_' + setting + '"]');
if (node) {
this.updateOptionsForMediaRange(node, capability);
node.parentNode.style.display = 'block';
}
return;
}
},
initCameraSelection: function(){
var streamLabel = Quagga.CameraAccess.getActiveStreamLabel();
return Quagga.CameraAccess.enumerateVideoDevices()
.then(function(devices) {
function pruneText(text) {
return text.length > 30 ? text.substr(0, 30) : text;
}
var $deviceSelection = document.getElementById("deviceSelection");
while ($deviceSelection.firstChild) {
$deviceSelection.removeChild($deviceSelection.firstChild);
}
devices.forEach(function(device) {
var $option = document.createElement("option");
$option.value = device.deviceId || device.id;
$option.appendChild(document.createTextNode(pruneText(device.label || device.deviceId || device.id)));
$option.selected = streamLabel === device.label;
$deviceSelection.appendChild($option);
});
});
},
attachListeners: function() {
var self = this;
self.initCameraSelection();
$(".controls").on("click", "button.stop", function(e) {
e.preventDefault();
Quagga.stop();
self._printCollectedResults();
});
$(".controls .reader-config-group").on("change", "input, select", function(e) {
e.preventDefault();
var $target = $(e.target),
value = $target.attr("type") === "checkbox" ? $target.prop("checked") : $target.val(),
name = $target.attr("name"),
state = self._convertNameToState(name);
console.log("Value of "+ state + " changed to " + value);
self.setState(state, value);
});
},
_printCollectedResults: function() {
var results = resultCollector.getResults(),
$ul = $("#result_strip ul.collector");
results.forEach(function(result) {
var $li = $('<li><div class="thumbnail"><div class="imgWrapper"><img /></div><div class="caption"><h4 class="code"></h4></div></div></li>');
$li.find("img").attr("src", result.frame);
$li.find("h4.code").html(result.codeResult.code + " (" + result.codeResult.format + ")");
$ul.prepend($li);
});
},
_accessByPath: function(obj, path, val) {
var parts = path.split('.'),
depth = parts.length,
setter = (typeof val !== "undefined") ? true : false;
return parts.reduce(function(o, key, i) {
if (setter && (i + 1) === depth) {
if (typeof o[key] === "object" && typeof val === "object") {
Object.assign(o[key], val);
} else {
o[key] = val;
}
}
return key in o ? o[key] : {};
}, obj);
},
_convertNameToState: function(name) {
return name.replace("_", ".").split("-").reduce(function(result, value) {
return result + value.charAt(0).toUpperCase() + value.substring(1);
});
},
detachListeners: function() {
$(".controls").off("click", "button.stop");
$(".controls .reader-config-group").off("change", "input, select");
},
applySetting: function(setting, value) {
var track = Quagga.CameraAccess.getActiveTrack();
if (track && typeof track.getCapabilities === 'function') {
switch (setting) {
case 'zoom':
return track.applyConstraints({advanced: [{zoom: parseFloat(value)}]});
case 'torch':
return track.applyConstraints({advanced: [{torch: !!value}]});
}
}
},
setState: function(path, value) {
var self = this;
if (typeof self._accessByPath(self.inputMapper, path) === "function") {
value = self._accessByPath(self.inputMapper, path)(value);
}
if (path.startsWith('settings.')) {
var setting = path.substring(9);
return self.applySetting(setting, value);
}
self._accessByPath(self.state, path, value);
console.log(JSON.stringify(self.state));
App.detachListeners();
Quagga.stop();
App.init();
},
inputMapper: {
inputStream: {
constraints: function(value){
if (/^(\d+)x(\d+)$/.test(value)) {
var values = value.split('x');
return {
width: {min: parseInt(values[0])},
height: {min: parseInt(values[1])}
};
}
return {
deviceId: value
};
}
},
numOfWorkers: function(value) {
return parseInt(value);
},
decoder: {
readers: function(value) {
if (value === 'ean_extended') {
return [{
format: "ean_reader",
config: {
supplements: [
'ean_5_reader', 'ean_2_reader'
]
}
}];
}
return [{
format: value + "_reader",
config: {}
}];
}
}
},
state: {
inputStream: {
type : "LiveStream",
constraints: {
width: {min: 640},
height: {min: 480},
facingMode: "environment",
aspectRatio: {min: 1, max: 2}
}
},
locator: {
patchSize: "medium",
halfSample: true
},
numOfWorkers: 2,
frequency: 10,
decoder: {
readers : [{
format: "code_128_reader",
config: {}
}]
},
locate: true
},
lastResult : null
};
App.init();
Quagga.onProcessed(function(result) {
var drawingCtx = Quagga.canvas.ctx.overlay,
drawingCanvas = Quagga.canvas.dom.overlay;
if (result) {
if (result.boxes) {
drawingCtx.clearRect(0, 0, parseInt(drawingCanvas.getAttribute("width")), parseInt(drawingCanvas.getAttribute("height")));
result.boxes.filter(function (box) {
return box !== result.box;
}).forEach(function (box) {
Quagga.ImageDebug.drawPath(box, {x: 0, y: 1}, drawingCtx, {color: "green", lineWidth: 2});
});
}
if (result.box) {
Quagga.ImageDebug.drawPath(result.box, {x: 0, y: 1}, drawingCtx, {color: "#00F", lineWidth: 2});
}
if (result.codeResult && result.codeResult.code) {
Quagga.ImageDebug.drawPath(result.line, {x: 'x', y: 'y'}, drawingCtx, {color: 'red', lineWidth: 3});
}
}
});
Quagga.onDetected(function(result) {
var code = result.codeResult.code;
if (App.lastResult !== code) {
App.lastResult = code;
var $node = null, canvas = Quagga.canvas.dom.image;
$node = $('<li><div class="thumbnail"><div class="imgWrapper"><img /></div><div class="caption"><h4 class="code"></h4></div></div></li>');
$node.find("img").attr("src", canvas.toDataURL());
$node.find("h4.code").html(code);
$("#result_strip ul.thumbnails").prepend($node);
}
});
});
Appreciate your help...Thank You

You can get the reference of your input control and set its value to the code variable in the onDetected code block.
Quagga.onDetected(function(result) {
var code = result.codeResult.code;
document.getElementById('MyInput').value = code;
});

How to update code to avoid "Undefined value"?

Recently I was working on a project with this extension and I have noticed that when I select "FIELD" option and enter a value everything works fine. But after I delete value from field and push enter whole app crash because of undefined value. Maybe someone could help me with code how to avoid this annoying crash?
Thx in advance!
Here is whole code.
/*global define*/
define(["qlik"], function(qlik) {
'use strict';
var BTN_SELECTED = 'qui-button-selected',
BTN = 'qui-button',
SELECT = 'qui-select',
INPUT = 'qui-input';
function createVariable(name) {
var app = qlik.currApp();
//from 2.1: check if variable exists
if (app.variable.getByName) {
app.variable.getByName(name).then(function() {
//variable already exist
}, function() {
//create variable
app.variable.create(name);
});
} else {
//create variable - ignore errors
app.variable.create(name);
}
}
function createElement(tag, cls, html) {
var el = document.createElement(tag);
if (cls) {
el.className = cls;
}
if (html !== undefined) {
el.innerHTML = html;
}
return el;
}
return {
initialProperties: {
variableValue: {},
variableName: "",
render: "f",
defaultValue: 0,
alternatives: []
},
definition: {
type: "items",
component: "accordion",
items: {
settings: {
uses: "settings",
items: {
variable: {
type: "items",
label: "Variable",
items: {
name: {
ref: "variableName",
label: "Name",
type: "string",
change: function(data) {
createVariable(data.variableName);
data.variableValue.qStringExpression = '=' + data.variableName;
}
},
render: {
type: "string",
component: "dropdown",
label: "Render as",
ref: "render",
options: [{
value: "b",
label: "Button"
}, {
value: "s",
label: "Select"
}, {
value: "f",
label: "Field"
}, {
value: "l",
label: "Slider"
}],
defaultValue: "f"
},
emptyVal: {
ref: "emptyVal",
label: "default(when empty)",
type: "string",
defaultValue: 0
},
alternatives: {
type: "array",
ref: "alternatives",
label: "Alternatives",
itemTitleRef: "label",
allowAdd: true,
allowRemove: true,
addTranslation: "Add Alternative",
items: {
value: {
type: "string",
ref: "value",
label: "Value"
},
label: {
type: "string",
ref: "label",
label: "Label",
expression: "optional"
}
},
show: function(data) {
return data.render === "b" || data.render === "s";
}
},
min: {
ref: "min",
label: "Min",
type: "number",
defaultValue: 0,
show: function(data) {
return data.render === "l";
}
},
max: {
ref: "max",
label: "Max",
type: "number",
defaultValue: 100,
show: function(data) {
return data.render === "l";
}
},
step: {
ref: "step",
label: "Step",
type: "number",
defaultValue: 1,
show: function(data) {
return data.render === "l";
}
}
}
}
}
}
}
},
paint: function($element, layout) {
var wrapper = createElement('div'),
ext = this;
empty = layout.emptyVal;
if (layout.render === 'b') {
layout.alternatives.forEach(function(alt) {
var clazz = alt.value === layout.variableValue ? BTN_SELECTED : BTN;
var btn = createElement('button', clazz, alt.label);
btn.onclick = function() {
qlik.currApp(ext).variable.setContent(layout.variableName, alt.value);
}
wrapper.appendChild(btn);
});
} else if (layout.render === 's') {
var sel = createElement('select', SELECT);
layout.alternatives.forEach(function(alt) {
var opt = createElement('option', undefined, alt.label);
opt.value = alt.value;
opt.selected = alt.value === layout.variableValue;
sel.appendChild(opt);
});
sel.onchange = function() {
qlik.currApp(ext).variable.setContent(layout.variableName, this.value);
}
wrapper.appendChild(sel);
} else if (layout.render === 'l') {
var range = createElement('input');
range.type = 'range';
range.min = layout.min || 0;
range.max = layout.max || 100;
range.step = layout.step || 1;
range.value = layout.variableValue;
range.title = layout.variableValue;
range.style.width = '98%';
range.onchange = function() {
qlik.currApp(ext).variable.setContent(layout.variableName, this.value);
}
wrapper.appendChild(range);
} else {
var fld = createElement('input', INPUT);
fld.type = 'number';
fld.value = layout.variableValue;
fld.onchange = function () {
if (this.value != "undifined") {
qlik.currApp(ext).variable.setContent(layout.variableName, this.value);
} else {
qlik.currApp(ext).variable.setContent(layout.variableName, 0);
}
}
wrapper.appendChild(fld);
}
var elem = $element[0];
if (elem.childNodes.length === 0) {
elem.appendChild(wrapper);
} else {
elem.replaceChild(wrapper, elem.childNodes[0]);
}
}
};
});

if (this.value != "undifined") {
Here, you are comparing value to the string "undifined" (which is also mistyped).
It seems you want to compare to the value undefined:
if (this.value !== undefined) {
or check the data type of value:
if (typeof this.value != "undefined") {

Implementing javascript Object.defineProperties

Hello I found some difficulties when implementing javascript Object.defineProperties:
var book1 = {};
Object.defineProperties(book1, {
_year: {
value: 2004
},
edition: {
value: 1
},
year: {
get : function() {
return this._year;
},
set : function(newValue) {
if ((newValue - this._year) > 0) {
this.edition += 1;
} else if ((newValue - this._year) < 0) {
this.edition -= 1;
}
this._year = newValue;
}
}
});
book1.year = 2005;
document.write(book1.edition); //get 1, expect 2
document.write('<br/>');
book1.year = 2006;
document.write(book1.edition); //get 1, expect 3
document.write('<br/>');
Browser: Chrome 17.0.963.56
Any answer is welcome.
Thank you.

You have to specify writable: true as a property descriptor of _year. By default, it's not writable, and assigning a value to a non-writable property doesn't have any effect.
I strongly recommend to activate the strict mode, because you will receive an error message when the assignment of a value to a read-only property fails.
"use strict"; // <---
Object.defineProperties(book1, {
_year: {
value: 2004
writable: true /* <-- writable set to true*/
},
edition: {
value: 1,
writable: true
},