findCodeChild()

在父元素内查找子 <code> 元素。

import { findCodeChild } from "@unifast/core";

签名

function findCodeChild(element: HastElement): HastElement | undefined

参数

element

属性	类型	默认值	描述
`type`	`"element"`	—	节点类型标识
`tagName`	`string`	—	HTML 标签名（通常是 `"pre"`）
`properties`	`Record<string, unknown>`	—	元素属性
`children`	`HastNode[]`	—	要检索的子节点

返回值

HastElement | undefined —— 第一个 tagName 为 "code" 的子元素；若不存在则返回 undefined。

用法

import { findCodeChild } from "@unifast/core";
import type { HastElement } from "@unifast/core";

const pre: HastElement = {
  type: "element",
  tagName: "pre",
  properties: {},
  children: [
    {
      type: "element",
      tagName: "code",
      properties: { className: ["language-js"] },
      children: [{ type: "text", value: "const x = 1;" }],
    },
  ],
};

const code = findCodeChild(pre);

console.log(code?.tagName);
// code

示例

在 pre 元素中查找 code

import { findCodeChild, extractLang, extractText } from "@unifast/core";
import type { HastElement } from "@unifast/core";

const pre: HastElement = {
  type: "element",
  tagName: "pre",
  properties: {},
  children: [
    {
      type: "element",
      tagName: "code",
      properties: { className: ["language-rust"] },
      children: [{ type: "text", value: 'fn main() { println!("hello"); }' }],
    },
  ],
};

const code = findCodeChild(pre);
if (code) {
  console.log(extractLang(code));
  // rust
  console.log(extractText(code));
  // fn main() { println!("hello"); }
}

不存在 code 子元素的情况

import { findCodeChild } from "@unifast/core";
import type { HastElement } from "@unifast/core";

const pre: HastElement = {
  type: "element",
  tagName: "pre",
  properties: {},
  children: [
    { type: "text", value: "plain preformatted text" },
  ],
};

const code = findCodeChild(pre);

console.log(code);
// undefined

搭配 visitHast 实现语法高亮

import { visitHast, findCodeChild, extractLang } from "@unifast/core";
import type { HastNode, HastElement } from "@unifast/core";

const tree: HastNode = {
  type: "root",
  children: [
    {
      type: "element",
      tagName: "pre",
      properties: {},
      children: [
        {
          type: "element",
          tagName: "code",
          properties: { className: ["language-js"] },
          children: [{ type: "text", value: "const x = 1;" }],
        },
      ],
    },
  ],
};

visitHast(tree, (node) => {
  if (node.type === "element" && node.tagName === "pre") {
    const code = findCodeChild(node);
    if (code) {
      const lang = extractLang(code);
      console.log(`Found code block with language: ${lang}`);
      // Found code block with language: js
    }
  }
});