Assign methods to the prototype object, instead of overwriting the prototype with a new object. Overwriting the prototype makes inheritance impossible: by resetting the prototype you’ll overwrite the base!
function Jedi() {
console.log('new jedi');
}
// bad
Jedi.prototype = {
fight: function fight() {
console.log('fighting');
},
block: function block() {
console.log('blocking');
}
};
// good
Jedi.prototype.fight = function fight() {
console.log('fighting');
};
Jedi.prototype.block = function block() {
console.log('blocking');
};
Methods can return this to help with method chaining.
// bad
Jedi.prototype.jump = function jump() {
this.jumping = true;
return true;
};
Jedi.prototype.setHeight = function setHeight(height) {
this.height = height;
};
var luke = new Jedi();
luke.jump(); // => true
luke.setHeight(20); // => undefined
// good
Jedi.prototype.jump = function jump() {
this.jumping = true;
return this;
};
Jedi.prototype.setHeight = function setHeight(height) {
this.height = height;
return this;
};
var luke = new Jedi();
luke.jump()
.setHeight(20);
It’s okay to write a custom toString() method, just make sure it works successfully and causes no side effects.
function Jedi(options) {
options || (options = {});
this.name = options.name || 'no name';
}
Jedi.prototype.getName = function getName() {
return this.name;
};
Jedi.prototype.toString = function toString() {
return 'Jedi - ' + this.getName();
};