no-unbound-this.md

No Unbound This

Using this in collection function callbacks only works if the callbacks are bound. Otherwise, this becomes the global object, which is a cause of a possible error. However, this is not true for arrow functions, since they do not create their own scope.

Rule Details

This rule takes no arguments.

The following patterns are considered warnings:

var y = _.map(x, function (t) {return this.f(t)})

var y = _.map(x, function (t) {return this.a + this.b})

The following patterns are not considered warnings:

var y = _.map(x, function(t) {
    return this.f(t)
}.bind(this))

var y = _.map(x, t => this.f(t))
        
var y = _.invokeMap(x, prop)

var y = _.map(x, prop)

var y = _.map(x, function(t) { 
    function f(i) {
        this.g(i)
    } 
    return f.apply(z, t)
})
 

When Not To Use It

This rule is only relevant for Lodash 4. If you don't use Lodash 4, you should not use this rule.