Open xgqfrms opened 5 years ago
https://www.runoob.com/js/js-void.html
<a href="javascript:void(0)">单击此处什么也不会发生</a>
<a href="javascript:void(alert('Warning!!!'))">点我!</a>
function getValue(){
var a,b,c;
a = void( b = 5, c = 7 );
document.write('a = ' + a + ' b = ' + b +' c = ' + c );
}
// a = undefined b = 5 c = 7
interface Animal {
speak(): void;
}
class Dog implements Animal {
food: string = '';
// override 字类覆盖父类方法
constructor(food: string) {
// super();
this.food = food;
}
speak() {
console.log("wang!");
}
eat(food: string) {
// ?? => !== null && !== void 0 ? :
// void 0 === undefined
console.log(food ?? this.food);
}
}
const puppy = new Dog('meat');
puppy.speak();
puppy.eat('🐶');
"use strict";
class Dog {
// override 字类覆盖父类方法
constructor(food) {
this.food = '';
// super();
this.food = food;
}
speak() {
console.log("wang!");
}
eat(food) {
// ?? => !== null && !== void 0 ? :
// void 0 === undefined
console.log(food !== null && food !== void 0 ? food : this.food);
}
}
const puppy = new Dog('meat');
puppy.speak();
puppy.eat('🐶');
void
anything ===undefined
void 0 === undefined;
// true
// void 0;
// undefined
void 1;
// undefined
// oid {};
// undefined
void [];
// undefined
void;
// Uncaught SyntaxError: Unexpected token ';'
https://gist.github.com/xgqfrms/f7196dc9f76ba13a80163fb6f910ed3b
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Shift + Alt + A === Block Commnets
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