Function htmBabelPlugin

packages/babel-plugin-htm/index.mjs:14–204

({ types: t }, options = {})

 * @param {boolean} [options.variableArity=true] If `false`, always passes exactly 3 arguments to the pragma function.
 */
export default function htmBabelPlugin({ types: t }, options = {}) {
	const pragmaString = options.pragma===false ? false : options.pragma || 'h';
	const pragma = pragmaString===false ? false : dottedIdentifier(pragmaString);
	const useBuiltIns = options.useBuiltIns;
	const useNativeSpread = options.useNativeSpread;
	const inlineVNodes = options.monomorphic || pragma===false;
	const importDeclaration = pragmaImport(options.import || false);

	function pragmaImport(imp) {
		if (pragmaString === false || imp === false) {
			return null;
		}
		const pragmaRoot = t.identifier(pragmaString.split('.')[0]);
		const { module, export: export_ } = typeof imp !== 'string' ? imp : {
			module: imp,
			export: null
		};

		let specifier;
		if (export_ === '*') {
			specifier = t.importNamespaceSpecifier(pragmaRoot);
		}
		else if (export_ === 'default') {
			specifier = t.importDefaultSpecifier(pragmaRoot);
		}
		else {
			specifier = t.importSpecifier(pragmaRoot, export_ ? t.identifier(export_) : pragmaRoot);
		}
		return t.importDeclaration([specifier], t.stringLiteral(module));
	}

	function dottedIdentifier(keypath) {
		const path = keypath.split('.');
		let out;
		for (let i=0; i<path.length; i++) {
			const ident = propertyName(path[i]);
			out = i===0 ? ident : t.memberExpression(out, ident);
		}
		return out;
	}

	function patternStringToRegExp(str) {
		const parts = str.split('/').slice(1);
		const end = parts.pop() || '';
		return new RegExp(parts.join('/'), end);
	}

	function propertyName(key) {
		if (t.isValidIdentifier(key)) {
			return t.identifier(key);
		}
		return t.stringLiteral(key);
	}

	function objectProperties(obj) {
		return Object.keys(obj).map(key => {
			const values = obj[key].map(valueOrNode =>
				t.isNode(valueOrNode) ? valueOrNode : t.valueToNode(valueOrNode)