mirror of https://github.com/lukechilds/node.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
90 lines
2.0 KiB
90 lines
2.0 KiB
'use strict';
|
|
|
|
require('../common');
|
|
const assert = require('assert');
|
|
const inherits = require('util').inherits;
|
|
const errCheck =
|
|
new RegExp('^TypeError: The super constructor to "inherits" must not be ' +
|
|
'null or undefined$');
|
|
|
|
|
|
// super constructor
|
|
function A() {
|
|
this._a = 'a';
|
|
}
|
|
A.prototype.a = function() { return this._a; };
|
|
|
|
// one level of inheritance
|
|
function B(value) {
|
|
A.call(this);
|
|
this._b = value;
|
|
}
|
|
inherits(B, A);
|
|
B.prototype.b = function() { return this._b; };
|
|
|
|
assert.strictEqual(B.super_, A);
|
|
|
|
const b = new B('b');
|
|
assert.strictEqual(b.a(), 'a');
|
|
assert.strictEqual(b.b(), 'b');
|
|
assert.strictEqual(b.constructor, B);
|
|
|
|
// two levels of inheritance
|
|
function C() {
|
|
B.call(this, 'b');
|
|
this._c = 'c';
|
|
}
|
|
inherits(C, B);
|
|
C.prototype.c = function() { return this._c; };
|
|
C.prototype.getValue = function() { return this.a() + this.b() + this.c(); };
|
|
|
|
assert.strictEqual(C.super_, B);
|
|
|
|
const c = new C();
|
|
assert.strictEqual(c.getValue(), 'abc');
|
|
assert.strictEqual(c.constructor, C);
|
|
|
|
// inherits can be called after setting prototype properties
|
|
function D() {
|
|
C.call(this);
|
|
this._d = 'd';
|
|
}
|
|
|
|
D.prototype.d = function() { return this._d; };
|
|
inherits(D, C);
|
|
|
|
assert.strictEqual(D.super_, C);
|
|
|
|
const d = new D();
|
|
assert.strictEqual(d.c(), 'c');
|
|
assert.strictEqual(d.d(), 'd');
|
|
assert.strictEqual(d.constructor, D);
|
|
|
|
// ES6 classes can inherit from a constructor function
|
|
class E {
|
|
constructor() {
|
|
D.call(this);
|
|
this._e = 'e';
|
|
}
|
|
e() { return this._e; }
|
|
}
|
|
inherits(E, D);
|
|
|
|
assert.strictEqual(E.super_, D);
|
|
|
|
const e = new E();
|
|
assert.strictEqual(e.getValue(), 'abc');
|
|
assert.strictEqual(e.d(), 'd');
|
|
assert.strictEqual(e.e(), 'e');
|
|
assert.strictEqual(e.constructor, E);
|
|
|
|
// should throw with invalid arguments
|
|
assert.throws(function() {
|
|
inherits(A, {});
|
|
}, /^TypeError: The super constructor to "inherits" must have a prototype$/);
|
|
assert.throws(function() {
|
|
inherits(A, null);
|
|
}, errCheck);
|
|
assert.throws(function() {
|
|
inherits(null, A);
|
|
}, /^TypeError: The constructor to "inherits" must not be null or undefined$/);
|
|
|