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Javascript Articles
Page 303 of 534
Wrap object properties of type string with arrays - JavaScript
For this, use Object.keys() along with reduce(). To display the result, we will also use concat().ExampleFollowing is the code −var details = { name: ["John", "David"], age1: "21", age2: "23" }, output = Object .keys(details) .reduce((obj, tempKey) => (obj[tempKey] = [].concat(details[tempKey]), obj), {}) console.log(output) To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo302.js.OutputThis will produce the following output on console −PS C:\Users\Amit\javascript-code> node demo302.js { name: [ 'John', 'David' ], age1: [ '21' ], age2: [ '23' ] }
Read MoreHow to merge specific elements inside an array together - JavaScript
Let’s say the following is our array −var values = [7,5,3,8,9,'/',9,5,8,2,'/',3,4,8];To merge specific elements, use map along with split().ExampleFollowing is the code −var values = [7,5,3,8,9,'/',9,5,8,2,'/',3,4,8]; var afterMerge = values.join('') .split(/(\d+)/). filter(Boolean). map(v => isNaN(v) ? v : +v); console.log(afterMerge);To run the above program, you need to use the following command −node fileName.js. Here, my file name is demo301.js.OutputThis will produce the following output on console −PS C:\Users\Amit\javascript-code> node demo301.js [ 75389, '/', 9582, '/', 348 ]
Read MoreGet the correct century from 2-digit year date value - JavaScript?
For this, you can use ternary operator based on some condition.ExampleFollowing is the code −const yearRangeValue = 18; const getCorrectCentury = dateValues => { var [date, month, year] = dateValues.split("-"); var originalYear = +year > yearRangeValue ? "20" + year : "18" + year; return new Date(date + "-" + month + "-" + originalYear).toLocaleDateString('en-GB') }; console.log(getCorrectCentury('10-JAN-19'));To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo300.js.OutputThis will produce the following output on console −PS C:\Users\Amit\javascript-code> node demo300.js 1/10/2019
Read MoreWhat is the “get” keyword before a function in a class - JavaScript?
The get keyword can be used as a getter function like C#, Java and other technologies.We set a function with get like the following in a class −class Employee { constructor(name) { this.name = name; } get fullName() { return this.name; } }ExampleFollowing is the code displaying an example of get −class Employee { constructor(name) { this.name = name; } get fullName() { return this.name; } } var employeeObject = new Employee("David Miller"); console.log(employeeObject.fullName);To run the above program, you need to use ...
Read MoreReplace multiple instances of text surrounded by specific characters in JavaScript?
Let’s say the following is our string. Some text is surrounded by special character hash(#) −var values = "My Name is #yourName# and I got #marks# in JavaScript subject";We need to replace the special character with valid values. For this, use replace() along with shift().ExampleFollowing is the code −var values = "My Name is #yourName# and I got #marks# in JavaScript subject"; const originalValue = ["David Miller", 97]; var result = values.replace(/#([^#]+)#/g, _ => originalValue.shift()); console.log(result);To run the above program, you need to use the following command −node fileName.js. Here, my file name is demo298.js.OutputThis will produce the following output ...
Read MoreMake JavaScript take HTML input from user, parse and display?
The HTML input value is a string. To convert the string to integer, use parseInt().ExampleFollowing is the code − Live Demo Document GetANumber function result() { var numberValue = document.getElementById("txtInput").value; if (!isNaN(numberValue)) console.log("The value=" + parseInt(numberValue)); else console.log("Please enter the integer value.."); } To run the above program, save the file name “anyName.html(index.html)”. Right click on the file and select the option “Open with ...
Read MoreWhat's the most efficient way to turn all the keys of an object to lower case - JavaScript?
Let’s say the following is our object −var details = { "STUDENTNAME": "John", "STUDENTAGE": 21, "STUDENTCOUNTRYNAME": "US" }As you can see above, the keys are in capital case. We need to turn all these keys to lower case. Use toLowerCase() for this.ExampleFollowing is the code −var details = { "STUDENTNAME": "John", "STUDENTAGE": 21, "STUDENTCOUNTRYNAME": "US" } var tempKey, allKeysOfDetails = Object.keys(details); var numberOfKey = allKeysOfDetails.length; var allKeysToLowerCase = {} while (numberOfKey--) { tempKey = allKeysOfDetails[numberOfKey]; allKeysToLowerCase[tempKey.toLowerCase()] = details[tempKey]; } console.log(allKeysToLowerCase);To run the above program, you need to use the following command −node ...
Read MoreHow to get id from tr tag and display it in a new td with JavaScript?
Let’s say the following is our table − StudentName StudentCountryName JohnDoe UK DavidMiller US To get id from tr tag and display it in a new td, use document.querySelectorAll(table tr).ExampleFollowing is the code − Live Demo Document td, th, table { border: 1px solid black; margin-left: 10px; ...
Read MoreES6 Default Parameters in nested objects – JavaScript
Yes, you can pass default parameters in nested objects.Following is the code −ExampleFollowing is the code −function callBackFunctionDemo({ cl: { callFunctionName = "callBackFunction", values = 100 } = {} } = {}) { console.log(callFunctionName); console.log(values); } //This will print the default value. // 100 callBackFunctionDemo(); //This will print the given value. //500 callBackFunctionDemo({ cl: { values: 500 } });To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo296.js.OutputThis will produce the following output on console −PS C:\Users\Amit\javascript-code> node demo296.js callBackFunction 100 callBackFunction 500
Read MoreHow to decrease size of a string by using preceding numbers - JavaScript?
Let’s say our original string is the following with repeated letters −var values = "DDAAVIDMMMILLERRRRR";We want to remove the repeated letters and precede letters with numbers. For this, use replace() along with regular expression.ExampleFollowing is the code −var values = "DDAAVIDMMMILLERRRRR"; var precedingNumbersInString = values.replace(/(.)\1+/g, obj => obj.length + obj[0]); console.log("The original string value=" + values); console.log("String value after preceding the numbers ="); console.log(precedingNumbersInString);To run the above program, you need to use the following command −node fileName.js. Here, my file name is demo295.js.OutputThis will produce the following output on console −PS C:\Users\Amit\javascript-code> node demo295.js The original string value=DDAAVIDMMMILLERRRRR String value ...
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