How to specify an element is a text one?

[ooker777]

This code:

import { fromHtml } from "hast-util-from-html";
import { select } from "hast-util-select";

const tree = fromHtml("<h1>Hi</h1>>", { fragment: true });
console.log(select("h1", tree)!.children[0].value);

creates this error

Property 'value' does not exist on type 'ElementContent'.
  Property 'value' does not exist on type 'Element'.

How can I fix that?

Also, why is the text considered as a child of the tag? Shouldn't the children property only contain other elements? The value property can move up to the object.

[wooorm]

TypeScript gives you a type error because you have a type error.
If you want types, use TS. TS will give you errors when you make problems. This is that.

How to use TS:

You store things in variables, and perform checks on them:

const tree = fromHtml("<h1>Hi</h1>>", { fragment: true }); // Root
const h1 = select("h1", tree) // Element
if (!h1) throw new Error("main heading missing")
const head = h1.children[0] // ElementContent
if (head.type !== 'text') throw new Error("there are non-text things in the head!")
console.log(head.value)

However, do not do you want you do. Your goal is to get the text of a heading. Headings can contain other things than text (as the types indicate). If you want text, use a tool for that:

import {toText} from 'hast-util-to-text'

const tree = fromHtml("<h1>Hi</h1>>", { fragment: true }); // Root
const h1 = select("h1", tree) // Element
if (!h1) throw new Error("main heading missing")
const text = toText(h1) // string

See also:

• https://unifiedjs.com/learn/recipe/narrow-node-typescript/
• https://unifiedjs.com/learn/guide/syntax-trees-typescript/
• https://unifiedjs.com/learn/recipe/tree-traversal-typescript/

Shouldn't the children property only contain other elements?

No, that is not needed. There is no such restriction.

The value property can move up to the object.

Anything could be done. But some things are not good things. This is not a good thing. There would be different sources of truth. Which will bite everyone in their butt.