Function is used as the return value
function f1() {
console.log ("F1 function start");
return function () {
console.log ("function is used as return value");
}
}
Get the data type of the variable num
Determine whether the object is of a certain type
var num = 10;
console.log(typeof num); //num
var obj = {};
console.log(obj instanceof Object); //true
//In this case, the data type of the object [object object] is output
console.log(Object.prototype.toString());
//The data type of the output array [object array]
console.log(Object.prototype.toString.call([]));
var arr = [10, 20, 30];
console.log(Object.prototype.toString.call(arr)); //[object Array]
var arr = [10, 20, 30];
console.log(Object.prototype.toString.call(arr)); // [object Array]
console.log(Object.prototype.toString.call(new Date()));//[object Date]
//Determine whether the object and the type passed in are of the same type
function getFunc(type) {
return function (obj) {
return Object.prototype.toString.call(obj) === type;
}
}
var ff = getFunc("[object Array]");
var result = ff([10, 20, 30]);
console.log(result); //true
var ff1 = getFunc("[object Object]");
var dt = new Date();
var result1 = ff1(dt);
console.log(result1); //false