extractText()

Recursively extract all text content from a HAST node.

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

Signature

function extractText(node: HastNode): string

Parameters

node

Property	Type	Default	Description
`type`	`string`	—	The node type (`"root"`, `"element"`, `"text"`, etc.)
`children`	`HastNode[]`	—	Child nodes (for `"root"` and `"element"` types)
`value`	`string`	—	Text content (for `"text"` type)

Returns

string — All text content concatenated from the node and its descendants.

Usage

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

const element: HastElement = {
  type: "element",
  tagName: "p",
  properties: {},
  children: [
    { type: "text", value: "Hello " },
    {
      type: "element",
      tagName: "strong",
      properties: {},
      children: [{ type: "text", value: "world" }],
    },
  ],
};

const text = extractText(element);

console.log(text);
// Hello world

Examples

Extract from a simple element

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

const heading: HastElement = {
  type: "element",
  tagName: "h1",
  properties: { id: "title" },
  children: [{ type: "text", value: "Getting Started" }],
};

console.log(extractText(heading));
// Getting Started

Extract from nested elements

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

const paragraph: HastElement = {
  type: "element",
  tagName: "p",
  properties: {},
  children: [
    { type: "text", value: "This is " },
    {
      type: "element",
      tagName: "em",
      properties: {},
      children: [
        { type: "text", value: "deeply " },
        {
          type: "element",
          tagName: "strong",
          properties: {},
          children: [{ type: "text", value: "nested" }],
        },
      ],
    },
    { type: "text", value: " content." },
  ],
};

console.log(extractText(paragraph));
// This is deeply nested content.

Empty element

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

const emptyDiv: HastElement = {
  type: "element",
  tagName: "div",
  properties: {},
  children: [],
};

console.log(extractText(emptyDiv));
// (empty string)

Generating heading slugs

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

const heading: HastElement = {
  type: "element",
  tagName: "h2",
  properties: {},
  children: [
    { type: "text", value: "API " },
    {
      type: "element",
      tagName: "code",
      properties: {},
      children: [{ type: "text", value: "Reference" }],
    },
  ],
};

const slug = extractText(heading).toLowerCase().replace(/\s+/g, "-");

console.log(slug);
// api-reference