zoukankan      html  css  js  c++  java
  • xgqfrms™, xgqfrms® : xgqfrms's offical website of GitHub!

    empty array bug

    
        const duplicationArray = (arr = [], times = 2, debug = false) => {
            let result = [];
            let temps = new Array(times);
            console.log(`temps =`, temps);
            temps.forEach(
                (item, i) => {
                    // undefined bug
                    console.log(`item =`, item);
                    let temp = arr;
                    result.concat(temp);
                    console.log(`result =`, result);
                }
            );
            // for (let i = 0; i < times; i++) {
            //     let temp = arr;
            //     result.concat(temp);
            // }
            if (debug) {
                console.log(`result =`, result.length);
            }
            return result;
        };
    
    

    solution

    Array.from()

    bug

    
    let temps = new Array(3);
    // (3) [empty × 3]
    temps.forEach(
        (item, i) => {
            // empty & undefined bug
            console.log(`item =`, item, i);
        }
    );
    
    

    OK

    
    let temps = Array.from(new Array(3));
    // (3) [undefined, undefined, undefined]
    temps.forEach(
        (item, i) => {
            // undefined ok
            console.log(`item =`, item, i);
            // item = undefined 0
        }
    );
    
    
  • 相关阅读:
    DOM
    JavaScript 数组的方法总结
    vuex 状态持久化插件 —— vuex-persistedstate
    移动端1px细线
    CSS多行文本并显示省略号
    Java面试题
    Git提交分支
    Redis的安装配置
    Spring IoC
    单例模式
  • 原文地址:https://www.cnblogs.com/xgqfrms/p/9661969.html
Copyright © 2011-2022 走看看