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1-js/3-object-basics/3-object-methods/8-chain-calls/solution.md

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+The solution is to return the object itself from every call.
+
+```js run
+let ladder = {
+  step: 0,
+  up() {
+    this.step++;
+*!*
+    return this;
+*/!*
+  },
+  down() {
+    this.step--;
+*!*
+    return this;
+*/!*
+  },
+  showStep() {
+    alert( this.step );
+*!*
+    return this;
+*/!*
+  }
+}
+
+ladder.up().up().down().up().down().showStep(); // 1
+```
+
+We also can write a single call per line. For long chains it's more readable:
+
+```js 
+ladder
+  .up()
+  .up()
+  .down()
+  .up()
+  .down()
+  .showStep(); // 1
+```
+

1-js/3-object-basics/3-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.