Javascript - Apply trim function to each string in an array
String.prototype.trim.apply is the Function.prototype.apply method without being bound to trim. map will invoke it with the string, the index and the array as arguments and nothing (undefined) for the thisArg - however, apply expects to be called on functions:
var apply = String.prototype.trim.apply;apply.call(undefined, x[0], 0, x) // TypeErrorWhat you can do is passing the trim function as the context for call:
[' aa ', ' bb '].map(Function.prototype.call, String.prototype.trim)// ['aa', 'bb']What happens here is
var call = Function.prototype.call, trim = String.prototype.trim;call.call(trim, x[0], 0, x) ≡ trim.call(x[0], 0, x) ≡ x[0].trim(0, x); // the arguments don't matter to trim
The simple variant without dependencies:
for (var i = 0; i < array.length; i++) { array[i] = array[i].trim() }ES6 variant:
const newArray = oldArray.map(string => string.trim())ES6 function variant:
const trimmedArray = array => array.map(string => string.trim())