Introduction to new features of numerical expansion

Numerical expansion mainly adds some new features, such as new methods and method adjustments

1. Binary numerical representation (use 0B as the prefix, b is indifferent Uppercase and lowercase) Octal numerical representation (use 0o as prefix)

{
  console.log('B',0B111110111);
  console.log(0o767);
}

　2. Number.isFinite (finite) Number. isNaN (not a number)

{
  console.log('15',Number.isFinite(15));//true
  console.log('NaN',Number.isFinite(NaN));//false
  console.log('1/0',Number.isFinite('true'/0));//false
  console.log('NaN',Number.isNaN(NaN));//true
  console.log('0',Number.isNaN(0));//false}

　3. Number.isInteger (determine whether it is an integer, note: the received parameter must be a number)

{
  console.log('25',Number.isInteger(25));//true
  console.log('25.0',Number.isInteger(25.0));//true
  console.log('25.1',Number.isInteger(25.1));//false
  console.log('25.1',Number.isInteger('25'));//false
}

　4. Number.MAX_SAFE_INTEGER (2 to the 53rd power) Number.MIN_SAFE_INTEGER (2 to the -53rd power) (these two are the upper and lower integers)

　You can use Number.isSafeInteger to determine whether it is within the above range

{
  console.log(Number.MAX_SAFE_INTEGER,Number.MIN_SAFE_INTEGER);
  console.log('10',Number.isSafeInteger(10));//true
  console.log('a',Number.isSafeInteger('a'));//false
}

　5. Math.trunc (get The integer part of the decimal is not rounded)

{
  console.log(4.1,Math.trunc(4.1));//4
  console.log(4.9,Math.trunc(4.9));//4
}

　6. Math.sign (Judge positive and negative numbers, return -1 for negative number, return 0 for 0, return 1 is a positive number)

{
  console.log('-5',Math.sign(-5));//-1
  console.log('0',Math.sign(0));//0
  console.log('5',Math.sign(5));//1
  console.log('50',Math.sign('50'));//1(传递的参数为字符串数字 仍然当做数字)
  console.log('foo',Math.sign('foo'));//NaN（传递的参数是字符串 返回NaN）
}

　7. Math.cbrt (returns the cube root of a number)

　

{
  console.log('-1',Math.cbrt(-1));//-1
  console.log('8',Math.cbrt(8));//2
}

　There are also some new APIs such as trigonometric functions and logarithms, which are not listed here

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