TD: for in with array : don't use it

itération sur les indices et non sur les valeurs

var arr = [ 'a', 'b', 'c' ];
for (var key in arr) { console.log(key); }
0
1
2

De plus,

 var arr = [ 'a', 'b', 'c' ];
 arr.foo = true;
 for (var key in arr) { console.log(key); }
0
1
2
foo

correction : hasOwnProperty(key) !

for (var key in arr) {
    if (arr.hasOwnProperty(key)) {
        console.log(key);
    }
}

Finalement, on choisit



for (var i=0; i<arr.length; i++) {
    console.log(arr[i]);
}

arr.forEach(function (elem) {
    console.log(elem);
});

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