Array.prototype.every()

every() metodu bir dizideki tüm elemanların verilen fonksiyonun testini geçip geçmediği kontrol eder. Bu metot true (doğru) yada false (yanlış) olarak ikilik değer döndürür. 

Note: Test edilen array boş ise bu metot true deger döndürür.

Söz dizimi

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

Parametreler

callback
Her elemanı test eden üç değişken alan bir fonksiyon:
element
İşlemde olan geçerli dizi elemanı.
indexOptional
İşlemde olan geçerli dizi elemanın indeksi .
arrayOptional
every tarafından çağrılan dizi.
thisArgOptional
Geri dönüş yapıldığında this olarak kullanıcak bir değer.

Dönüş değeri

Geri dönüş fonksiyonu her bir dizi elemanı için bir truthy deger dondürse true. Aksi takdirde, false.

Description

The every method executes the provided callback function once for each element present in the array until it finds the one where callback returns a falsy value. If such an element is found, the every method immediately returns false. Otherwise, if callback returns a truthy value for all elements, every returns true. callback is invoked only for indexes of the array which have assigned values; it is not invoked for indexes which have been deleted or which have never been assigned values.

callback is invoked with three arguments: the value of the element, the index of the element, and the Array object being traversed.

If a thisArg parameter is provided to every, it will be used as callback's this value. Otherwise, the value undefined will be used as its this value.  The this value ultimately observable by callback is determined according to the usual rules for determining the this seen by a function.

every does not mutate the array on which it is called.

The range of elements processed by every is set before the first invocation of callback. Therefore, callback will not run on elements that are appended to the array after the call to every begins. If existing elements of the array are changed, their value as passed to callback will be the value at the time every visits them. Elements that are deleted are not visited.

every acts like the "for all" quantifier in mathematics. In particular, for an empty array, it returns true. (It is vacuously true that all elements of the empty set satisfy any given condition.)

Örnekler

Tüm dizi elemanlarının büyüklüğünün test edilmesi

Aşağıdaki örnekte tüm dizi elemanlarının 10'dan büyük yada eşit olma durumu test edilir.

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

Ok fonksiyonlarını kullanma

Ok fonksiyonları aynı testin daha kısa söz dizimi ile yapılmasını sağlar.

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

Polyfill

every was added to the ECMA-262 standard in the 5th edition, and it may not be present in other implementations of the standard. You can work around this by inserting the following code at the beginning of your scripts, allowing use of every in implementations which do not natively support it. This algorithm is exactly the one specified in ECMA-262, 5th edition, assuming Object and TypeError have their original values and that callbackfn.call evaluates to the original value of Function.prototype.call

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. Let O be the result of calling ToObject passing the this 
    //    value as the argument.
    var O = Object(this);

    // 2. Let lenValue be the result of calling the Get internal method
    //    of O with the argument "length".
    // 3. Let len be ToUint32(lenValue).
    var len = O.length >>> 0;

    // 4. If IsCallable(callbackfn) is false, throw a TypeError exception.
    if (typeof callbackfn !== 'function') {
      throw new TypeError();
    }

    // 5. If thisArg was supplied, let T be thisArg; else let T be undefined.
    if (arguments.length > 1) {
      T = thisArg;
    }

    // 6. Let k be 0.
    k = 0;

    // 7. Repeat, while k < len
    while (k < len) {

      var kValue;

      // a. Let Pk be ToString(k).
      //   This is implicit for LHS operands of the in operator
      // b. Let kPresent be the result of calling the HasProperty internal 
      //    method of O with argument Pk.
      //   This step can be combined with c
      // c. If kPresent is true, then
      if (k in O) {

        // i. Let kValue be the result of calling the Get internal method
        //    of O with argument Pk.
        kValue = O[k];

        // ii. Let testResult be the result of calling the Call internal method
        //     of callbackfn with T as the this value and argument list 
        //     containing kValue, k, and O.
        var testResult = callbackfn.call(T, kValue, k, O);

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

Specifications

Specification Status Comment
ECMAScript 5.1 (ECMA-262)
The definition of 'Array.prototype.every' in that specification.
Standard Initial definition. Implemented in JavaScript 1.6.
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Array.prototype.every' in that specification.
Standard
ECMAScript Latest Draft (ECMA-262)
The definition of 'Array.prototype.every' in that specification.
Draft

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
everyChrome Full support YesEdge Full support 12Firefox Full support 1.5IE Full support 9Opera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesFirefox Android Full support 4Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android Full support Yesnodejs Full support Yes

Legend

Full support  
Full support

See also