39 lines
610 B
Markdown
39 lines
610 B
Markdown
importance: 2
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---
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# Chaining
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There's a `ladder` object that allows to go up and down:
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```js
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let ladder = {
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step: 0,
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up() {
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this.step++;
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},
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down() {
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this.step--;
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},
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showStep: function() { // shows the current step
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alert( this.step );
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}
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};
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```
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Now, if we need to make several calls in sequence, can do it like this:
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```js
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ladder.up();
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ladder.up();
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ladder.down();
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ladder.showStep(); // 1
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```
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Modify the code of `up` and `down` to make the calls chainable, like this:
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```js
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ladder.up().up().down().showStep(); // 1
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```
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Such approach is widely used across JavaScript libraries.
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