Array.prototype.every
Tests whether all elements in the array pass the test implemented by the provided function
Syntax
array.every(callbackFn, thisArg?)Parameters
| Parameter | Type | Description |
|---|---|---|
| callbackFn | (element, index, array) => boolean | Function to test each element |
| thisArg | any | Value to use as this when executing callbackFn |
Return Value
true if all elements pass the test, false otherwise
Examples
const numbers = [2, 4, 6, 8];
const allEven = numbers.every(n => n % 2 === 0);
console.log(allEven); // trueconst ages = [18, 21, 25, 30];
const allAdults = ages.every(age => age >= 18);
console.log(allAdults); // trueconst values = [1, 2, 3, -1];
console.log(values.every(v => v > 0)); // falseUnderstanding Array.prototype.every
The Array.prototype.every method in JavaScript tests whether all elements in the array pass the test implemented by the provided function. It belongs to the Array object and is one of the most widely used methods for working with array values in modern JavaScript and TypeScript applications.
The method signature is array.every(callbackFn, thisArg?). It accepts 2 parameters: callbackFn, thisArg. When called, it returns true if all elements pass the test, false otherwise. Understanding when and how to use every() helps you write more expressive, readable code.
Common use cases for Array.prototype.every include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like array-some, array-filter, array-find, enabling you to chain operations together for complex data manipulation pipelines.
Browser support for Array.prototype.every is excellent across all modern browsers including Chrome, Firefox, Safari, and Edge. It is also fully supported in Node.js and Deno. For older environments, transpilation with Babel or a polyfill may be needed.
Browser Compatibility
Supported in all modern browsers (Chrome, Firefox, Safari, Edge) and Node.js. Part of the ECMAScript standard.
Related Methods
Array.prototype.someTests whether at least one element in the array passes the test implemented by the provided function
Array.prototype.filterCreates a shallow copy of a portion of a given array, filtered down to just the elements that pass the test implemented by the provided function
Array.prototype.findReturns the first element in the provided array that satisfies the provided testing function
Array.prototype.includesDetermines whether an array includes a certain value among its entries, returning true or false
More Array Methods
Other methods in the Array object
Related Tools
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