add each value to array javascript code example

Example 1: how to append item to an array in foreach javascript

for (var i = 0; i < a.length; i++) {
    if (a[i] == 1) a.push(5);
    console.log(a[i]);
}

Example 2: javascript add 1 to each element in array

var numberarr2 = numberarr.map( function(value) { 
    return value - 1; 
} );