svelte/src/compiler/compile/nodes/Text.ts

import Node from './shared/Node';
import Component from '../Component';
import TemplateScope from './shared/TemplateScope';
import { INode } from './interfaces';

// Whitespace inside one of these elements will not result in
// a whitespace node being created in any circumstances. (This
// list is almost certainly very incomplete)
const elements_without_text = new Set([
	'audio',
	'datalist',
	'dl',
	'optgroup',
	'select',
	'video',
]);

export default class Text extends Node {
	type: 'Text';
	data: string;
	synthetic: boolean;

	constructor(component: Component, parent: INode, scope: TemplateScope, info: any) {
		super(component, parent, scope, info);
		this.data = info.data;
		this.synthetic = info.synthetic || false;
	}

	should_skip() {
		if (/\S/.test(this.data)) return false;

		const parent_element = this.find_nearest(/(?:Element|InlineComponent|Head)/);
		if (!parent_element) return false;

		if (parent_element.type === 'Head') return true;
		if (parent_element.type === 'InlineComponent') return parent_element.children.length === 1 && this === parent_element.children[0];

		// svg namespace exclusions
		if (/svg$/.test(parent_element.namespace)) {
			if (this.prev && this.prev.type === "Element" && this.prev.name === "tspan") return false;
		}

		return parent_element.namespace || elements_without_text.has(parent_element.name);
	}
}