Arrow functions are not yet supported in Safari, IE and Opera Mini. #javascript #es6 #tip
caniuse.com/#feat=arrow-fu…

// ES5
var posNums = nums.filter(function (x) {
return x > 0;
});

// #ES6
var posNums = nums.filter(x => x > 0);

#javascript #tip

#ES6 arrow functions do not have their own 'this'. The value of this inside an arrow function is always inherited from the enclosing scope.

Code is temporary. It exists while it is useful.
If code is replaced by better code, good!
If code can be deleted, celebrate! #JavaScript

Shorthand for #es6 arrow function with single argument:
var f = x => {
return x*x;
};

// equivalent to
var f = (x) => {
return x*x;
};

Shorthand for #es6 arrow function with single return statement:
var f = (x) => x*x;

// equivalent to
var f = (x) => {
return x*x;
};

ES6 arrow functions:

var normalFunc = function(x) {
return x * x;
};

var arrowFunc = (x) => {
return x*x;
};

#javascript #tips

#javascript 'new' keyword:
function A() {
this.x = 1;
this.y = 2;
}

var a1 = new A();
var a2 = new A();
a1.x++;
a1.x; // 2
a2.x; // 1

Usage of the 'arguments' local variable:

function foo() {
console.log(arguments);
}

foo(1, 2, 3, 4); // [1, 2, 3, 4]

#javascript #tip

Use #es6 in your javascript code today with @babeljs!
hacks.mozilla.org/2015/06/es6-in…

Convert CSV to array:

var str = "apple, peach, orange";
var fruitsArray = str.split(","); // ['apple', 'peach', 'orange']

#javascript #tip

#JavaScript array to csv:

var fruits = ['apple', 'peaches', 'oranges'];
var str = fruits.valueOf();
// apple,peaches,oranges

#js #tips

Remove duplicates from array:

var deduped = [ 1, 1, 'a', 'a'].filter(function (x, i, arr) {
return arr.indexOf(x) === i;
}); // [1, 'a']

Flattening an array :

var myArray = [[1, 2], [], [3]];
var flatArray = [].concat.apply([], myArray);
// flatArray is [1, 2, 3]

#javascript

Getting a UNIX timestamp in #JavaScript:

var dateTime = Date.now();
var timestamp = Math.floor(dateTime / 1000);

#tips #js

To see a function's code, concatenate it with the empty string :

console.log(funcVariable + '');

#javascript #tips

The && operator first evaluates the expression on the left. If falsy, false is returned; it does not bother to evaluate the right operand.

JavaScript Falsy Values: null, false, 0 undefined, NaN, and “” (this last item is an empty string). #javascript #tips

Infinity, which is a special number like NaN, is truthy; it is not falsy, while NaN is falsy. #javascript #tips

Calculate max/min in an array:

var arr = [1, 2, 3, 4];
Math.max.apply(null, arr) // 4
Math.min.apply(null, arr) // 1

#javascript #tips