_.bind method

Every day at AcademicWorks, the Engineering Team has a Dev Sync where we share something we learned from the day before. Often times we'll hear about some new movie, a cool Kickstarter project, or an interesting ruby gem.

What I learned

As I mentioned earlier this week, the keyword this in Javascript is confusing.

If we aren't careful, the context for any function we run can be different from what we expect. The keyword this can refer to the object that is calling the function. But sometimes we want this to be explicitly bound or set always to same object.

Here at AW, we use underscore's _.bind method. One specific example is how we use bind within a jQuery event listener to explicitly bind our function to the instance of a module that was instantiated with a constructor function.

this.$el.on(
  'click',
  '.js-target-container',
  _.bind(this.toggleActionButton, this)
)

More resources

• Underscore bind docs
• Youtube: Javascript Context Tutorial - What makes Javascript Weird...and Awesome Pt5
• JavaScript’s Apply, Call, and Bind Methods are Essential for JavaScript Professionals