css-doodle/src/parser/parse-svg-path.js

A web component for visual art & creative coding

import { scan, iterator } from './tokenizer.js';

const commands = 'MmLlHhVvCcSsQqTtAaZz';
const relatives = 'mlhvcsqtaz';

const cache = new Map();

function parse(input) {
  if (cache.has(input)) {
    return cache.get(input);
  }

  let iter = iterator(scan(input));
  let temp = {};
  let result = {
    commands: [],
    valid: true
  };
  while (iter.next()) {
    let { curr } = iter.get();
    if (curr.isSpace() || curr.isSymbol(',')) {
      continue;
    }
    if (curr.isWord()) {
      if (temp.name) {
        result.commands.push(temp);
        temp = {};
      }
      temp.name = curr.value;
      temp.value = [];
      if (!commands.includes(curr.value)) {
        temp.type = 'unknown';
        result.valid = false;
      } else if (relatives.includes(curr.value)) {
        temp.type = 'relative';
      } else {
        temp.type = 'absolute';
      }
    } else if (temp.value) {
      let value = curr.value;
      if (curr.isNumber()) {
        value = Number(curr.value);
      } else if (curr.isSymbol('-') || curr.isSymbol('+')) {
        let { next } = iter.get();
        if (next && next.isNumber()) {
          iter.next();
          value = Number(curr.value + next.value);
        }
      }
      temp.value.push(value);
    } else if (!temp.name) {
      result.valid = false;
    }
  }
  if (temp.name) {
    result.commands.push(temp);
  }

  cache.set(input, result);
  return result;
}

export default parse;