通过一个实例来对比面向过程和面向对象的编程思维

需求

• 实现一个简易的计算器效果
• 计算 (250 + 10) * 4 / 2 的结果

面向过程

function jia(a, b) {
    return a + b;
}
function jian(a, b) {
    return a - b;
}
function chen(a, b) {
    return a * b;
}
function chu(a, b) {
    if (a === 0) {
        throw new Error('logic error');
    }
    if (b == 0) {
        return 0;
    }
    return a / b;
}
let result = jia(250, 10);
    result = chen(result, 4);
    result = chu(result, 2);
console.log(result);

面向对象

class Calc {
    constructor(){
        this.result = 0;
    }
    jia(num) {
        this.result += this.a;
        return this;
    }
    jian(num) {
        this.result -= this.a;
        return this;
    }
    chen(num) {
        this.result *= this.a;
        return this;
    }
    chu(num) {
        this.result /= this.a;
        return this;
    }
    getResult() {
        return this.result;
    }
}
let calc = new Calc();
let result = calc.jia(250).jia(10).chen(4).chu(2).getResult();
console.log(result);

分析总结

面向过程的优缺点

• 优点: 易于理解和阅读
• 缺点: 复用程度低, 代码零散

面向对象的优缺点

• 优点: 易于理解和阅读
• 缺点: 代码复用度高, 灵活性高, 易于扩展

补充(面向对象的es5代码)

function Calc() {
    this.result = 0;
}
Calc.prototype.jia(num) {
    this.result += num;
    return this;
}
Calc.prototype.jian(num) {
    this.result -= num;
    return this;
}
Calc.prototype.chen(num) {
    this.result *= num;
    return this;
}
Calc.prototype.chu(num) {
    this.result /= num;
    return this;
}
let calc = new Calc();
let result = calc.jia(250).jia(10).chen(4).chu(2).getResult();
console.log(result);