@gravityforms/gulp-tasks/src/scripts/utils/lexer.js

Configurable Gulp tasks for use in Gravity Forms projects.

const tokens = require( './tokens/tokens' );

/**
 * @function getUniqSymbol
 * @description Get a unique symbol to use as a placeholder for tokens.
 *
 * @since 1.9.6
 *
 * @return {number} The unique symbol.
 */
function getUniqSymbol() {
	return Date.now() + Math.random();
}

/**
 * @function identifyNewToken
 * @description Identify a token type based on the line being parsed.
 *
 * @since 1.9.6
 *
 * @param {string} line The line being parsed.
 *
 * @return {object} The new token.
 */
function identifyNewToken( line ) {
	for ( const type in tokens ) {
		const token = tokens[ type ];
		const test = new token( line );
		if ( test.isToken() ) {
			return test;
		}
	}

	return new tokens.plainTextToken( line );
}

/**
 * @function lexFile
 * @description Lex the given file text for tokens.
 *
 * @since 1.9.6
 *
 * @param {string} text The file text to be lexxed.
 *
 * @return {object} The tokens and symbolized text.
 */
function lexFile( text ) {
	const lines = text.split( '\n' );
	let symbolizedText = '';
	let currentToken = false;
	const foundTokens = {};

	lines.forEach( ( lineItem, idx ) => {
		const line = lineItem;
		const prevLine = idx === 0 ? '' : lines[ idx - 1 ];

		if ( ! currentToken ) {
			currentToken = identifyNewToken( line );
		}

		if (
			( currentToken && currentToken.endConditionReached( line, prevLine ) ) ||
			( currentToken.type() === 'plaintext' && identifyNewToken( line ).type() !== 'plaintext' )
		) {
			const symbol = getUniqSymbol();
			symbolizedText += symbol;
			foundTokens[ symbol ] = currentToken;
			currentToken = identifyNewToken( line );
		}

		if ( currentToken && ! currentToken.endConditionReached( line, prevLine ) ) {
			currentToken.addLine( line );
		}

		if ( currentToken && idx === lines.length - 1 ) {
			const symbol = getUniqSymbol();
			symbolizedText += symbol;
			foundTokens[ symbol ] = currentToken;
		}
	} );

	return { foundTokens, symbolizedText };
}

/**
 * @function parseToken
 * @description Parse a token into its correct contents.
 *
 * @since 1.9.6
 *
 * @param {string} sym         The symbol to replace with the rendered content.
 * @param {object} token       The current token being evaluated.
 * @param {string} updatedText The current file text containing symbols to be replaced.
 *
 * @return {string} The file text with the contents updated with token markup.
 */
function parseToken( sym, token, updatedText ) {
	return updatedText.replace( sym, token.getContent() );
}

/**
 * @function processTokens
 * @description Process the tokens found in a file.
 *
 * @since 1.9.6
 *
 * @param {Array}  foundTokens The current tokens to be processed.
 * @param {string} text        The file text containing the symbols to replace.
 *
 * @return {string} The file text with the contents updated with tokens markup.
 */
function processTokens( foundTokens, text ) {
	let updatedText = text;

	for ( const sym in foundTokens ) {
		const token = foundTokens[ sym ];
		updatedText = parseToken( sym, token, updatedText );
	}

	return updatedText;
}

/**
 * @function lex
 * @description Lex a file for tokens and it's symbolized version for processing.
 *
 * @since 1.9.6
 *
 * @param {string} text The file text to process.
 *
 * @return {object} The tokens and symbolized text found for the file.
 */
function lex( text ) {
	const { foundTokens, symbolizedText } = lexFile( text );

	return { tokens: foundTokens, symbolizedText };
}

module.exports = { lex, processTokens };