logical-expression-parser/tokenizer.js

Logical expression parser and evaluates result, suitable for permissions management

const TokenType = require('./token-type');

const Tokenizer = exp => {
  let literal = '';
  const tokens = [];
  for (const char of exp) {
    const code = char.charCodeAt(0);
    switch (code) {
      case TokenType.PAR_OPEN:
      case TokenType.PAR_CLOSE:
      case TokenType.OP_NOT:
      case TokenType.BINARY_AND:
      case TokenType.BINARY_OR:
        if (literal) {
          tokens.push({
            type: TokenType.LITERAL,
            value: literal
          });
          literal = '';
        }

        tokens.push({
          type: code,
          value: char
        });
        break;
      default:
        literal += char;
    }
  }

  if (literal)
    tokens.push({
      type: TokenType.LITERAL,
      value: literal
    });

  return tokens;
};

module.exports = Tokenizer;