Bind context Look at the example where we loose context in function and need to bind it if assign it to external variable.
const obj = {
number: 5,
showNumber: function() { alert(obj.number) },
showNumberViaThis: function() { alert(this.number) }
}
obj.showNumber() // 5
obj.showNumberViaThis() // 5
const myShowNumber = obj.showNumber
myShowNumber() // 5
const myShowNumberViaThis = obj.showNumberViaThis
myShowNumberViaThis() // undefined
const myShowNumberViaThisWithBind = obj.showNumberViaThis.bind(obj)
myShowNumberViaThisWithBind() // 5