查找替换函数中未使用的对象键

Question

我有一个替换函数，它从一个对象中获取值并像这样替换模板文字：

let componentJSON = [
  { "template": "<div class='${layout} ${border}'></div>" },
  {
    "layout": "grid",
    "color": "blue",
    "border": "primary"
  }
];

const template = componentJSON[0].template
const classes = componentJSON[1]

let html = template.replace(/$\{(.*?)\}/g, (match, key) => classes[key]);

console.log(html);

是否可以 return（或 consoleLog）未使用的对象键？在这种情况下 "color": "blue"

Answer 1

我想你可以从对象中删除属性，然后检查对象最后还剩下什么。

let componentJSON = [
  { "template": "<div class='${layout} ${border}'></div>" },
  {
    "layout": "grid",
    "color": "blue",
    "border": "primary"
  }
];

const template = componentJSON[0].template
const classes = componentJSON[1]

const html = template.replace(
  /$\{(.*?)\}/g,
  (match, key) => {
    const str = classes[key];
    delete classes[key];
    return str;
  }
);

console.log(componentJSON[1]);

Answer 2

跟踪使用的密钥，然后从原始密钥集中过滤它们

let componentJSON = [
  { "template": "<div class='${layout} ${border}'></div>" },
  {
    "layout": "grid",
    "color": "blue",
    "border": "primary"
  }
];

const [ { template }, classes ] = componentJSON;

const usedKeys = new Set();
let html = template.replace(/$\{(.*?)\}/g, (match, key) => 
  (usedKeys.add(key), classes[key]));

console.log(html);

const unused = Object.fromEntries(
  Object.entries(classes).filter(([ key ]) => !usedKeys.has(key))
);

console.log("unused", unused);

查找替换函数中未使用的对象键

Find the object key that's not used in a replace function

javascript

replace