Comment puis-je vérifier si un tableau contient une valeur en JavaScript

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console.log(['joe', 'jane', 'mary'].includes('jane')); //true

console.log(['joe', 'jane', 'mary'].indexOf('jane') >= 0); //true

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function contains(a, obj) {     var i = a.length;     while (i--) {        if (a[i] === obj) {            return true;        }     }     return false; } 

Array.prototype.contains = function(obj) {     var i = this.length;     while (i--) {         if (this[i] === obj) {             return true;         }     }     return false; } 

alert([1, 2, 3].contains(2)); // => true alert([1, 2, 3].contains('2')); // => false 

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[1, 2, 3].indexOf(1) => 0 ["foo", "bar", "baz"].indexOf("bar") => 1 [1, 2, 3].indexOf(4) => -1 

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[1, 2, 3].includes(2); // true [1, 2, 3].includes(4); // false 

[1, 2, 3].includes(3, 3); // false [1, 2, 3].includes(3, -1); // true 

[1, 2, NaN].includes(NaN); // true 

new Array(5).includes(undefined); // true 

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const items = [ {a: '1'}, {a: '2'}, {a: '3'} ]  items.some(item => item.a === '3')  // returns true items.some(item => item.a === '4')  // returns false 

if (items.some(item => item.a === '3')) {   // do something }