Migrating to Arrow function from Normal function JS

Question

In my project, I don't wanna use construction function () {}, instead of that I wanna use () => {} or () => (). Code below. In first example I can see this, in second case this undefined. So I wonder, Is it possible way to make () => {} see this? I tried to use () => {}.bind(this) did not work and ({ context: this }) => {} did not work either.

// Example 1
describe('Currency converter', () => {
  it('should be shown on the page', function () {
    console.log(this); // { bla: ..., blabla: ... }
    return this.browser
      .url('/')
      .keys(['currence', '\uE007'])
      .isExisting('.converter-form')
      .then((exists) => {
        assert.ok(exists, 'currence did not show');
      });
  });
});

// Example 2
describe('Currency converter', () => {
  it('should be shown on the page', () => {
    console.log(this) // undefinded
    return this.browser
      .url('/')
      .keys(['currence', '\uE007'])
      .isExisting('.converter-form')
      .then((exists) => {
        assert.ok(exists, 'currence did not show');
      });
  });
});

You are sending the `window` all the way down, you have to use `function` if you want to create a `this `reference. Since you are probably using `'use strict'` then `this` on `window` is `undefined` — Pavlo, Mar 25 '18 at 13:13
hermione might be using `.call` or `.apply` and arrow functions neuter the context passed. ie. `() => { ... }` is the same as `(function() { ... }).bind(this)` — Daniel A. White, Mar 25 '18 at 13:14
if you using fat arrow it should save you the need of using ".bind()" — happyZZR1400, Mar 25 '18 at 13:15
@happyZZR1400 i'm guessing its something hermione is passing — Daniel A. White, Mar 25 '18 at 13:16

score 1 · Accepted Answer · answered Mar 25 '18 at 13:15

1

No! Arrow functions don't have a their own value for this, even if you try to bind them. You have to use the long form.

answered Mar 25 '18 at 13:15

Ben West

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Migrating to Arrow function from Normal function JS

1 Answers1