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1-js/4-object-basics/04-object-methods/8-chain-calls/task.md

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