https://davidwalsh.name/es7-es8-features
// padStart(desiredLength, textToPrepend)
// No text
''.padStart(10, 'Hi') // 'HiHiHiHiHi'
// Some text
'def'.padStart(6, 'abc') // 'abcdef'
// Only use what gets to length
'5678'.padStart(7, '1234') // '1235678'
// padEnd(desiredLength, textToAppend)
'23'.padEnd(8, '0') // '23000000'
// Object literal
Object.entries({ 'a': 'A', 'b': 'B' });
// [["a","A"],["b","B"]]
Object.entries(obj).forEach(([key, value]) => {
console.log(`${key} ${value}`);
}); // "a 5", "b 7", "c 9"
_.each(obj, (k,v) => console.log(`${k} `${v}))
// String
Object.entries('david')
// [["0","d"],["1","a"],["2","v"],["3","i"],["4","d"]
// Object literal
Object.values({ 'a': 23, 'b': 19 })
// [23, 19]
// Array-like object (order not preserved)
Object.values({ 80: 'eighty', 0: 1, 1: 'yes' })
// [1, 'yes', 'eighty']
// String
Object.values('strategery')
// [ 's', 't', 'r', 'a', 't', 'e', 'g', 'e', 'r', 'y' ]
// Array
Object.values([1, 2, 3]) // [1, 2, 3]
// getFoo is property which isn't enumerable
var my_obj = Object.create({}, { getFoo: { value: () => this.foo } });
my_obj.foo = 'bar';
console.log(Object.values(my_obj)); // ['bar']
['a', 'b', 'c'].includes('a')
// returns boolean
['a','b','c'].indexOf('a') ? console.log('yup') : console.log('nope')
nope
['a','b','c'].indexOf('a') !== -1 ? console.log('yup') : console.log('nope')
yup
['a','b','c'].includes('a') ? console.log('yup') : console.log('nope')
yup
['a', 'b', 'c'].includes('d')
// false
// 2 to the power of 8
Math.pow(2, 8)
// 256
// ..becomes
2 ** 8
// 256
function es8(
var1,
var2,
var3,
) {
// ...
}ES9 Feature
// Lookahead assertion
/\d+(?=%)/.exec("100% of US presidents have been male")
// 100
// Lookbehind assertion
/(?<=\$)\d+/.exec("Benjamin Franklin is on the $100 bill")
// 100