The function to be called
The value of this provided for the call to fn. If the function is not in strict mode,
null and undefined will be replaced with the global object, and primitive values will be converted to objects.
Optional argArray: ArrayLike<any>An array-like object, specifying the arguments with which fn should be called, or null or
undefined if no arguments should be provided to the function.
The result of calling the function with the specified this value and arguments.
0.9.8
// min / max number in an array
let max = fnApply(Math.max, null, [ 21, 42, 84, 168, 7, 3 ]);
// 168
let min = fnApply(Math.min, null, [ 21, 42, 84, 168, 7, 3 ]);
// 3
const module1 = {
prefix: "Hello",
x: 21,
getX() {
return this.x;
},
log(value: string) {
return this.prefix + " " + value + " : " + this.x
}
};
// The 'this' parameter of 'getX' is bound to 'module'.
module1.getX(); // 21
module1.log("Darkness"); // Hello Darkness : 21
// Create a new function 'boundGetX' with the 'this' parameter bound to 'module'.
let module2 = {
prefix: "my",
x: 42
};
// Call the function of module1 with module2 as it's this
fnApply(module1.getX, module2); // 42
fnApply(module1.log, module2, [ "friend" ]); // my friend : 42
The
fnApplyfunction calls the specifiedfnfunction with the giventhisArgas thethisvalue, and the optionalargArrayarguments provided as an array (or an Array-Like Object).Normally, when calling a function, the value of
thisinside the function is the object that the function was accessed on. WithfnApply(), you can assign an arbitrary value as this when calling an existing function, without first attaching the function to the object as a property. This allows you to use methods of one object as generic utility functions.You can also use any kind of object which is ArrayLike as the second parameter. In practice, this means that it needs to have a length property, and integer ("index") properties in the range (0..length - 1). For example, you could use a NodeList, or a custom object like
{ 'length': 2, '0': 'eat', '1': 'bananas' }. You can also usearguments.