javascript Count the occurrences of a value in an array

ByAnurag batra August 1, 2022June 30, 2022

const countOccurrences = (arr, val) => arr.reduce((a, v) => (v === val ? a + 1 : a), 0);

// Examples
countOccurrences([2, 1, 3, 3, 2, 3], 2);                // 2
countOccurrences(['a', 'b', 'a', 'c', 'a', 'b'], 'a');  // 3

Here is what the above code is Doing:
1. The reduce() method is called on the array.
2. The callback function is invoked for each element in the array.
3. The callback function takes two arguments: the accumulator and the current element.
4. The accumulator is initialized to 0.
5. If the current element is equal to the value we’re looking for, the accumulator is incremented by 1.
6. The accumulator is returned.

Javascript Examples

base 16 number javascript

ByAnurag batra July 27, 2022June 30, 2022

var number = 0x1b; console.log(number);//27 Here is what the above code is Doing: 1. We create a variable called number and assign it the value 0x1b. 2. We print the value of number to the console. 3. The value of number is 27.

Javascript Examples

intl collator

ByAnurag batra July 7, 2022June 30, 2022

console.log([‘b’, ‘a’, ‘z’, ‘ä’].sort(new Intl.Collator(‘de’).compare)); console.log([‘b’, ‘a’, ‘z’, ‘ä’].sort(new Intl.Collator(‘sv’).compare)); // [‘a’, ‘ä’, ‘b’, ‘z’] // [‘a’, ‘b’, ‘z’, ‘ä’] Here is what the above code is Doing: 1. The first console.log() statement is sorting the array using the default sort order. 2. The second console.log() statement is sorting the array using the German sort…

js arrays check if there is intersection

Javascript Examples

js arrays check if there is intersection

ByAnurag batra July 11, 2022June 30, 2022

// Use a combination of Array.prototype.filter and Array.prototype.includes: const filteredArray = array1.filter(value => array2.includes(value)); Here is what the above code is Doing: 1. We use Array.prototype.filter to filter out all values in array1 that are not present in array2. 2. We use Array.prototype.includes to check if the current value (value) is present in array2. 3….

Javascript Examples

nodejs fs delete non empty directory

ByAnurag batra July 25, 2022June 30, 2022

var rimraf = require(“rimraf”); rimraf(“/some/directory”, function () { console.log(“done”); }); Here is what the above code is Doing: 1. It’s requiring the rimraf module. 2. It’s calling rimraf with the directory to delete and a callback function. 3. The callback function is called when the directory is deleted.

convert celsius to fahrenheit javascript

Javascript Examples

convert celsius to fahrenheit javascript

ByAnurag batra August 5, 2022June 30, 2022

const celsiusToFahrenheit = celsius => celsius * 9/5 + 32; const fahrenheitToCelsius = fahrenheit => (fahrenheit – 32) * 5/9; // Examples celsiusToFahrenheit(15); // 59 fahrenheitToCelsius(59); // 15 Here is what the above code is Doing: 1. We define a function celsiusToFahrenheit that takes a parameter celsius. 2. We define a function fahrenheitToCelsius that takes…

get selected value of select2 dropdown in jquery

Javascript Examples

get selected value of select2 dropdown in jquery

ByAnurag batra July 23, 2022June 30, 2022

//initialize $(‘#mySelect2’).select2(‘data’); //get selected value $(‘#mySelect2’).find(‘:selected’); Here is what the above code is Doing: 1. Initialize the select2 plugin on the select element. 2. Get the selected value from the select element.

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