142 lines
3.3 KiB
JavaScript
142 lines
3.3 KiB
JavaScript
'use strict';
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const { Node, Block } = require('./Node');
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const languages = require('./languages');
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const constants = {
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ESCAPED_CHAR_REGEX: /^\\./,
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QUOTED_STRING_REGEX: /^(['"`])((?:\\.|[^\1])+?)(\1)/,
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NEWLINE_REGEX: /^\r*\n/
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};
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const parse = (input, options = {}) => {
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if (typeof input !== 'string') {
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throw new TypeError('Expected input to be a string');
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}
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const cst = new Block({ type: 'root', nodes: [] });
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const stack = [cst];
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const name = (options.language || 'javascript').toLowerCase();
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const lang = languages[name];
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if (typeof lang === 'undefined') {
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throw new Error(`Language "${name}" is not supported by strip-comments`);
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}
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const { LINE_REGEX, BLOCK_OPEN_REGEX, BLOCK_CLOSE_REGEX } = lang;
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let block = cst;
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let remaining = input;
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let token;
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let prev;
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const source = [BLOCK_OPEN_REGEX, BLOCK_CLOSE_REGEX].filter(Boolean);
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let tripleQuotes = false;
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if (source.every(regex => regex.source === '^"""')) {
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tripleQuotes = true;
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}
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/**
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* Helpers
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*/
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const consume = (value = remaining[0] || '') => {
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remaining = remaining.slice(value.length);
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return value;
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};
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const scan = (regex, type = 'text') => {
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const match = regex.exec(remaining);
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if (match) {
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consume(match[0]);
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return { type, value: match[0], match };
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}
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};
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const push = node => {
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if (prev && prev.type === 'text' && node.type === 'text') {
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prev.value += node.value;
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return;
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}
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block.push(node);
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if (node.nodes) {
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stack.push(node);
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block = node;
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}
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prev = node;
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};
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const pop = () => {
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if (block.type === 'root') {
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throw new SyntaxError('Unclosed block comment');
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}
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stack.pop();
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block = stack[stack.length - 1];
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};
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/**
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* Parse input string
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*/
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while (remaining !== '') {
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// escaped characters
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if ((token = scan(constants.ESCAPED_CHAR_REGEX, 'text'))) {
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push(new Node(token));
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continue;
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}
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// quoted strings
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if (block.type !== 'block' && (!prev || !/\w$/.test(prev.value)) && !(tripleQuotes && remaining.startsWith('"""'))) {
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if ((token = scan(constants.QUOTED_STRING_REGEX, 'text'))) {
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push(new Node(token));
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continue;
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}
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}
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// newlines
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if ((token = scan(constants.NEWLINE_REGEX, 'newline'))) {
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push(new Node(token));
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continue;
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}
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// block comment open
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if (BLOCK_OPEN_REGEX && options.block && !(tripleQuotes && block.type === 'block')) {
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if ((token = scan(BLOCK_OPEN_REGEX, 'open'))) {
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push(new Block({ type: 'block' }));
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push(new Node(token));
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continue;
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}
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}
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// block comment close
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if (BLOCK_CLOSE_REGEX && block.type === 'block' && options.block) {
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if ((token = scan(BLOCK_CLOSE_REGEX, 'close'))) {
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token.newline = token.match[1] || '';
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push(new Node(token));
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pop();
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continue;
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}
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}
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// line comment
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if (LINE_REGEX && block.type !== 'block' && options.line) {
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if ((token = scan(LINE_REGEX, 'line'))) {
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push(new Node(token));
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continue;
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}
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}
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// Plain text (skip "C" since some languages use "C" to start comments)
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if ((token = scan(/^[a-zABD-Z0-9\t ]+/, 'text'))) {
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push(new Node(token));
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continue;
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}
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push(new Node({ type: 'text', value: consume(remaining[0]) }));
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}
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return cst;
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};
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module.exports = parse;
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