IT干货|前端：8个Javascript小技巧，让你写的代码有腔调，指尖有风

var one = ‘1’;

var two = ‘2’;

var numberOne = Number(one); //1

var numberTwo = parseInt(two); //2

function convertNumber(str){

return +str;

}

convertNumber(‘1234’); 

//1234

convertNumber(‘abc’);

//NaN

var one = ‘1’;

var numberOne = +one; //1

var list = [1, 2, 3, 4];

list = [ ];

var list = [1,2,3,4];

list.length = 0;

ComponentModule= [‘call-back’,’router’,’nav’]

PageModule = [‘home’,’payment’]

AppModule = [ ]. concat(ComponentModule,PageModule)

var array1 = [1,2,3]; 

var array2 = [4,5,6]; 

console.log(array1.push.apply(array1, array2)); // [1,2,3,4,5,6];

function toArray(…args){

  console.log(args);

}

toArray(1,2,3); //[1,2,3]

var arr=[1,2,3];

//var arr2=Array.from(arr);

var arr2=[...arr];

arr.pop();

console.log(arr); //[1,2]

console.log(arr2); //[1,2,3]

var one = 1;

var two = 2;

var three = '3';

var result = one + two + three;

 // 会得到 "33" 而非 "123"

var one = 1;

var two = 2;

var three = '3';

var result = ''.concat(one, two, three); // 得到 "123"

Math.max(1, 2, 3, 4); // 4

Math.min(1, 2, 3, 4); // 1

var numbers = [1, 2, 3, 4];

Math.max.apply(null, numbers) // 4

Math.min.apply(null, numbers) // 1

var numbers = [1, 2, 3, 4];

Math.max(...numbers) // 4

Math.min(...numbers) // 1

var  a;

console.log(a) // undefined

a = a || ‘default value’

console.log(a)  // default value

a = a || ‘new value’

console.log(a)   // default value