Interpolator.js

import * as utils from './utils.js';
import baseLogger from './logger.js';

function deepFindWithDefaults(
  data,
  defaultData,
  key,
  keySeparator = '.',
  ignoreJSONStructure = true,
) {
  let path = utils.getPathWithDefaults(data, defaultData, key);
  if (!path && ignoreJSONStructure && typeof key === 'string') {
    path = utils.deepFind(data, key, keySeparator);
    if (path === undefined) path = utils.deepFind(defaultData, key, keySeparator);
  }
  return path;
}

class Interpolator {
  constructor(options = {}) {
    this.logger = baseLogger.create('interpolator');

    this.options = options;
    this.format = (options.interpolation && options.interpolation.format) || ((value) => value);
    this.init(options);
  }

  /* eslint no-param-reassign: 0 */
  init(options = {}) {
    if (!options.interpolation) options.interpolation = { escapeValue: true };

    const {
      escape,
      escapeValue,
      useRawValueToEscape,
      prefix,
      prefixEscaped,
      suffix,
      suffixEscaped,
      formatSeparator,
      unescapeSuffix,
      unescapePrefix,
      nestingPrefix,
      nestingPrefixEscaped,
      nestingSuffix,
      nestingSuffixEscaped,
      nestingOptionsSeparator,
      maxReplaces,
      alwaysFormat,
    } = options.interpolation;

    this.escape = escape !== undefined ? escape : utils.escape;
    this.escapeValue = escapeValue !== undefined ? escapeValue : true;
    this.useRawValueToEscape = useRawValueToEscape !== undefined ? useRawValueToEscape : false;

    this.prefix = prefix ? utils.regexEscape(prefix) : prefixEscaped || '{{';
    this.suffix = suffix ? utils.regexEscape(suffix) : suffixEscaped || '}}';

    this.formatSeparator = formatSeparator || ',';

    this.unescapePrefix = unescapeSuffix ? '' : unescapePrefix || '-';
    this.unescapeSuffix = this.unescapePrefix ? '' : unescapeSuffix || '';

    this.nestingPrefix = nestingPrefix
      ? utils.regexEscape(nestingPrefix)
      : nestingPrefixEscaped || utils.regexEscape('$t(');
    this.nestingSuffix = nestingSuffix
      ? utils.regexEscape(nestingSuffix)
      : nestingSuffixEscaped || utils.regexEscape(')');

    this.nestingOptionsSeparator = nestingOptionsSeparator || ',';

    this.maxReplaces = maxReplaces || 1000;

    this.alwaysFormat = alwaysFormat !== undefined ? alwaysFormat : false;

    // the regexp
    this.resetRegExp();
  }

  reset() {
    if (this.options) this.init(this.options);
  }

  resetRegExp() {
    const getOrResetRegExp = (existingRegExp, pattern) => {
      if (existingRegExp && existingRegExp.source === pattern) {
        existingRegExp.lastIndex = 0;
        return existingRegExp;
      }
      return new RegExp(pattern, 'g');
    };

    this.regexp = getOrResetRegExp(this.regexp, `${this.prefix}(.+?)${this.suffix}`);
    this.regexpUnescape = getOrResetRegExp(
      this.regexpUnescape,
      `${this.prefix}${this.unescapePrefix}(.+?)${this.unescapeSuffix}${this.suffix}`,
    );
    this.nestingRegexp = getOrResetRegExp(
      this.nestingRegexp,
      `${this.nestingPrefix}(.+?)${this.nestingSuffix}`,
    );
  }

  interpolate(str, data, lng, options) {
    let match;
    let value;
    let replaces;

    const defaultData =
      (this.options && this.options.interpolation && this.options.interpolation.defaultVariables) ||
      {};

    function regexSafe(val) {
      return val.replace(/\$/g, '$$$$');
    }

    const handleFormat = (key) => {
      if (key.indexOf(this.formatSeparator) < 0) {
        const path = deepFindWithDefaults(
          data,
          defaultData,
          key,
          this.options.keySeparator,
          this.options.ignoreJSONStructure,
        );
        return this.alwaysFormat
          ? this.format(path, undefined, lng, { ...options, ...data, interpolationkey: key })
          : path;
      }

      const p = key.split(this.formatSeparator);
      const k = p.shift().trim();
      const f = p.join(this.formatSeparator).trim();

      return this.format(
        deepFindWithDefaults(
          data,
          defaultData,
          k,
          this.options.keySeparator,
          this.options.ignoreJSONStructure,
        ),
        f,
        lng,
        {
          ...options,
          ...data,
          interpolationkey: k,
        },
      );
    };

    this.resetRegExp();

    const missingInterpolationHandler =
      (options && options.missingInterpolationHandler) || this.options.missingInterpolationHandler;

    const skipOnVariables =
      options && options.interpolation && options.interpolation.skipOnVariables !== undefined
        ? options.interpolation.skipOnVariables
        : this.options.interpolation.skipOnVariables;

    const todos = [
      {
        // unescape if has unescapePrefix/Suffix
        regex: this.regexpUnescape,
        safeValue: (val) => regexSafe(val),
      },
      {
        // regular escape on demand
        regex: this.regexp,
        safeValue: (val) => (this.escapeValue ? regexSafe(this.escape(val)) : regexSafe(val)),
      },
    ];
    todos.forEach((todo) => {
      replaces = 0;
      /* eslint no-cond-assign: 0 */
      while ((match = todo.regex.exec(str))) {
        const matchedVar = match[1].trim();
        value = handleFormat(matchedVar);
        if (value === undefined) {
          if (typeof missingInterpolationHandler === 'function') {
            const temp = missingInterpolationHandler(str, match, options);
            value = typeof temp === 'string' ? temp : '';
          } else if (options && Object.prototype.hasOwnProperty.call(options, matchedVar)) {
            value = ''; // undefined becomes empty string
          } else if (skipOnVariables) {
            value = match[0];
            continue; // this makes sure it continues to detect others
          } else {
            this.logger.warn(`missed to pass in variable ${matchedVar} for interpolating ${str}`);
            value = '';
          }
        } else if (typeof value !== 'string' && !this.useRawValueToEscape) {
          value = utils.makeString(value);
        }
        const safeValue = todo.safeValue(value);
        str = str.replace(match[0], safeValue);
        if (skipOnVariables) {
          todo.regex.lastIndex += value.length;
          todo.regex.lastIndex -= match[0].length;
        } else {
          todo.regex.lastIndex = 0;
        }
        replaces++;
        if (replaces >= this.maxReplaces) {
          break;
        }
      }
    });
    return str;
  }

  nest(str, fc, options = {}) {
    let match;
    let value;

    let clonedOptions;

    // if value is something like "myKey": "lorem $(anotherKey, { "count": {{aValueInOptions}} })"
    function handleHasOptions(key, inheritedOptions) {
      const sep = this.nestingOptionsSeparator;
      if (key.indexOf(sep) < 0) return key;

      const c = key.split(new RegExp(`${sep}[ ]*{`));

      let optionsString = `{${c[1]}`;
      key = c[0];
      optionsString = this.interpolate(optionsString, clonedOptions);
      const matchedSingleQuotes = optionsString.match(/'/g);
      const matchedDoubleQuotes = optionsString.match(/"/g);
      if (
        (matchedSingleQuotes && matchedSingleQuotes.length % 2 === 0 && !matchedDoubleQuotes) ||
        matchedDoubleQuotes.length % 2 !== 0
      ) {
        optionsString = optionsString.replace(/'/g, '"');
      }

      try {
        clonedOptions = JSON.parse(optionsString);

        if (inheritedOptions) clonedOptions = { ...inheritedOptions, ...clonedOptions };
      } catch (e) {
        this.logger.warn(`failed parsing options string in nesting for key ${key}`, e);
        return `${key}${sep}${optionsString}`;
      }

      // assert we do not get a endless loop on interpolating defaultValue again and again
      if (clonedOptions.defaultValue && clonedOptions.defaultValue.indexOf(this.prefix) > -1)
        delete clonedOptions.defaultValue;
      return key;
    }

    // regular escape on demand
    while ((match = this.nestingRegexp.exec(str))) {
      let formatters = [];

      clonedOptions = { ...options };
      clonedOptions =
        clonedOptions.replace && typeof clonedOptions.replace !== 'string'
          ? clonedOptions.replace
          : clonedOptions;
      clonedOptions.applyPostProcessor = false; // avoid post processing on nested lookup
      delete clonedOptions.defaultValue; // assert we do not get a endless loop on interpolating defaultValue again and again

      /**
       * If there is more than one parameter (contains the format separator). E.g.:
       *   - t(a, b)
       *   - t(a, b, c)
       *
       * And those parameters are not dynamic values (parameters do not include curly braces). E.g.:
       *   - Not t(a, { "key": "{{variable}}" })
       *   - Not t(a, b, {"keyA": "valueA", "keyB": "valueB"})
       */
      let doReduce = false;
      if (match[0].indexOf(this.formatSeparator) !== -1 && !/{.*}/.test(match[1])) {
        const r = match[1].split(this.formatSeparator).map((elem) => elem.trim());
        match[1] = r.shift();
        formatters = r;
        doReduce = true;
      }

      value = fc(handleHasOptions.call(this, match[1].trim(), clonedOptions), clonedOptions);

      // is only the nesting key (key1 = '$(key2)') return the value without stringify
      if (value && match[0] === str && typeof value !== 'string') return value;

      // no string to include or empty
      if (typeof value !== 'string') value = utils.makeString(value);
      if (!value) {
        this.logger.warn(`missed to resolve ${match[1]} for nesting ${str}`);
        value = '';
      }

      if (doReduce) {
        value = formatters.reduce(
          // eslint-disable-next-line no-loop-func
          (v, f) =>
            this.format(v, f, options.lng, { ...options, interpolationkey: match[1].trim() }),
          value.trim(),
        );
      }

      // Nested keys should not be escaped by default #854
      // value = this.escapeValue ? regexSafe(utils.escape(value)) : regexSafe(value);
      str = str.replace(match[0], value);
      this.regexp.lastIndex = 0;
    }
    return str;
  }
}

export default Interpolator;