JavaScript
Bind, Apply and Call
Callbacks and Promises
Error Handling
Map, Reduce, Filter
Objects
Prototypical Inheritance
Regular Expressions You can train for Regular Expressions in HackerRank. There is a special section.
Scope and Closures
this
Functions
Function in JS are first class citizens and you should know them well (assigned to a variable, passed as an argument, returned from another, etc.).
Output of this:
console.log(square(5));
/* ... */
function square(n) { return n * n; }
Output of this:
console.log(square(5));
var square = function(n) {
return n * n;
}
Why do you do this?
var simpleLibrary = function() {
var simpleLibrary = {
a,
b,
add: function(a, b) {
return a + b;
},
subtract: function(a, b) {
return a - b;
}
}
return simpleLibrary;
}();
If more than one parameter has the same name in a function definition, the last occurrence “shadows” the preceding occurrences. Ref