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Array.prototype.every() - JavaScript | MDN

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Array.prototype.every()

Baseline Widely available

This feature is well established and works across many devices and browser versions. Its been available across browsers since 2015 ..

every() , , .

: true .

In this article

arr.every(callback(currentValue[, index[, array]])[, thisArg])

callback

, :

currentValue

.

index

.

array

, .

thisArg

. , this callback.

true truthy . , false.

every() callback , , , callback (, false Boolean). , every() false. , callback true , every() true. callback , ; , .

callback : , , .

every() thisArg, callback this. this undefined. , this, callback, this, .

every() , .

, every(), callback. , every(), callback. , , callback, , every() ; .

every() . , true . (vacuously true) (.) .

:

, , 10.

js
function isBigEnough(element, index, array) {
  return element >= 10;
}
[12, 5, 8, 130, 44].every(isBigEnough); // false
[12, 54, 18, 130, 44].every(isBigEnough); // true

:

.

js
[12, 5, 8, 130, 44].every((elem) => elem >= 10); // false
[12, 54, 18, 130, 44].every((elem) => elem >= 10); // true

every() ECMA-262 5- ; . , , every() , . , ECMA-262 5- ; Object TypeError callback.call Function.prototype.call().

js
if (!Array.prototype.every) {
  Array.prototype.every = function (callbackfn, thisArg) {
    "use strict";
    var T, k;

    if (this == null) {
      throw new TypeError("this is null or not defined");
    }

    // 1.  O    ToObject  
    //    this,    .
    var O = Object(this);

    // 2.  lenValue      Get
    //     O   "length".
    // 3.  len  ToUint32(lenValue).
    var len = O.length >>> 0;

    // 4.  IsCallable(callbackfn)  false,   TypeError.
    if (typeof callbackfn !== "function") {
      throw new TypeError();
    }

    // 5.  thisArg ,  T  thisArg;   T  undefined.
    if (arguments.length > 1) {
      T = thisArg;
    }

    // 6.  k  0.
    k = 0;

    // 7.  k < len,  
    while (k < len) {
      var kValue;

      // a.  Pk  ToString(k).
      //           in
      // b.  kPresent     
      //    HasProperty  O   Pk.
      //          c
      // c.  kPresent  true, 
      if (k in O) {
        // i.  kValue      Get
        //     O   Pk.
        kValue = O[k];

        // ii.  testResult      Call
        //      callbackfn   T   this   ,
        //      kValue, k  O.
        var testResult = callbackfn.call(T, kValue, k, O);

        // iii.  ToBoolean(testResult)  false,  false.
        if (!testResult) {
          return false;
        }
      }
      k++;
    }
    return true;
  };
}

Specification
ECMAScript 2027 LanguageSpecification
# sec-array.prototype.every


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