关于ES6字符串的扩展详解

"\u0061"
// "a"

for (let codePoint of 'foo') {
  console.log(codePoint)
}
// "f"
// "o"
// "o"

$('#result').append(
  'There are <b>' + basket.count + '</b> ' +
  'items in your basket, ' +
  '<em>' + basket.onSale +
  '</em> are on sale!'
);

$('#result').append(`
  There are <b>${basket.count}</b> items
   in your basket, <em>${basket.onSale}</em>
  are on sale!
`);

let s = 'Hello world!';

s.startsWith('Hello') // true
s.endsWith('!') // true
s.includes('o') // true

let s = 'Hello world!';

s.startsWith('world', 6) // true
s.endsWith('Hello', 5) // true
s.includes('Hello', 6) // false

'x'.repeat(3) // "xxx"
'hello'.repeat(2) // "hellohello"
'na'.repeat(0) // ""

'x'.padStart(5, 'ab') // 'ababx'
'x'.padStart(4, 'ab') // 'abax'

'x'.padEnd(5, 'ab') // 'xabab'
'x'.padEnd(4, 'ab') // 'xaba'

const s = '  abc  ';

s.trim() // "abc"
s.trimStart() // "abc  "
s.trimEnd() // "  abc"