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apply()  Function  instance method

Description

Calls a function with a given this value and arguments provided as an array.

Syntax


Signature Description
aFunction.apply(thisArg[, argsArray])Calls a function with a given this value and arguments provided as an array.

Parameters


Parameter Description
thisArgThe value of this provided for the call to the function.
argsArrayThe arguments with which the function should be called, or null or undefined if no arguments required.

Examples

Below is an example of using the apply() method for chaining.


function Country(name, capital) {
  this.name = name;
  this.capital = capital;
  return this;
}
function County(name, capital, county) {
  Country.apply(this, arguments);
  this.county = county;
}
County.prototype = new Country();
// Define custom override function for County toString().
County.prototype.toString = function CountyToString() {  
  var county = this.name + ' ' + this.capital + ' ' + this.county;  
  return county;  
}
function Town(name, capital, county, town) {
  County.apply(this, arguments);
  this.town = town;
}
Town.prototype = new County();
// Define custom override function for Town toString().
Town.prototype.toString = function TownToString() {  
  var town = this.name + ' ' + this.capital + ' ' + 
             this.county + ' ' + this.town;  
  return town;  
}
var essex = new County('England', 'London', 'Essex');
alert(essex.toString());
alert(essex.constructor);

var barking = new Town('England', 'London', 'Essex', 'Barking');
alert(barking.toString());
alert(barking.constructor);

Press the button below to action the above code:

Related Tutorials

JavaScript Intermediate Tutorials - Lesson 8 - Functions



  

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