ractive/lib/parse.js

Next-generation DOM manipulation

/* eslint-env node */
const { reducePromiseFunctions, Ractive } = require('./util').Ractive;

const help = `
    parse

      Read a template on STDIN or from a file via the -i option, and output JSON or
      a similar JS object, depending on the CSP flag and whether or not there are
      expressions in the template, to STDOUT or a file via the -o option.

      -i, --input {file} - file to parse, otherwise STDIN
      -o, --output {file} - file to write, otherwise STDOUT
      -t, --text-only - text only
      -x, --nocsp - don't output expression functions
      -d, --delimiters {open} {close} - set the plain mustache delimiters (default {{ }})
      -s, --static {open} {close} - set the static mustache delimiters (default [[ ]])
      -r, --triple {open} {close} - set the triple mustache delimiters (default {{{ }}})
      -p, --static-triple {open} {close} - set the static triple delimiters (default [[[ ]]])
      -u, --escape-unicode - export non-ASCII characters in strings as UTF escapes
`;

function parse(string, opts) {
  const tpl = Ractive.parse(string, opts);
  if (opts.templateProcessors)
    return reducePromiseFunctions(opts.templateProcessors, tpl).then(tpl => {
      stringify(tpl, opts);
    });
  else return Promise.resolve(stringify(tpl, opts));
}

// https://gist.github.com/mathiasbynens/1243213
function escape(string) {
  return string.replace(/[^]/g, char => {
    const code = char.charCodeAt();

    if (code < 256) return char;

    const escape = code.toString(16);
    const long = escape.length > 2;
    return `\\${long ? 'u' : 'x'}${('0000' + escape).slice(long ? -4 : -2)}`;
  });
}

const ident = /^[a-zA-Z_$][a-zA-Z0-9_$]*$/;
function safeKey(string) {
  if (ident.test(string)) return string;
  else return JSON.stringify(string);
}

function stringify(tpl, opts) {
  let result;

  if (tpl.e) {
    let str = '{';
    let i = 0;
    for (const k in tpl) {
      if (i++ > 0) str += ',';
      if (k === 'e') {
        str += 'e:{';
        let i = 0;
        for (const k in tpl.e) {
          if (i++ > 0) str += ',';
          str += `${JSON.stringify(k)}:${tpl.e[k].toString()}`;
        }
        str += '}';
      } else {
        str += `${safeKey(k)}:${toString(tpl[k], opts)}`;
      }
    }
    result = str + '}';
  } else {
    result = toString(tpl, opts);
  }

  if (opts && opts.escapeUnicode) result = escape(result);

  return result;
}

function toString(thing, opts) {
  if (Array.isArray(thing)) {
    return '[' + thing.map(v => toString(v, opts)).join(',') + ']';
  } else if (typeof thing === 'object') {
    let str = '{';
    let trail = false;
    for (const k in thing) {
      if (thing[k] === undefined) continue;
      if (trail) str += ',';
      str += safeKey(k) + ':' + stringify(thing[k], opts);
      trail = true;
    }
    str += '}';
    return str;
  } else {
    return JSON.stringify(thing);
  }
}

module.exports = { help, parse, stringify };