Method getVariantCharacterSet

src/Encoder/BaudotCode.js:263–307

* Composes the character set for the given variant name. * @param {string} name Variant name * @return {array|null} Character set array or null if it not defined

(name)

   * @return {array|null} Character set array or null if it not defined
   */
  getVariantCharacterSet (name) {
    // Return cached character set, if available
    if (this._variantCharacterSet[name] !== undefined) {
      return this._variantCharacterSet[name]
    }

    // Find variant spec by name
    const spec = variants.find(variant => variant.name === name)
    if (spec === undefined) {
      return null
    }

    // Retrieve character set
    let characterSet = (spec.characterSet || []).slice()

    // Extend character set if this variant extends another one
    if (spec.extends) {
      const parent = this.getVariantCharacterSet(spec.extends)
      if (parent !== null) {
        characterSet = parent.slice()
      }
    }

    // Apply overrides
    if (spec.overrides) {
      for (const i in spec.overrides) {
        characterSet[i] = spec.overrides[i]
      }
    }

    // Map string chars to code points
    for (let i = 0; i < characterSet.length; i++) {
      const entry = characterSet[i]
      if (entry !== 'FS' && entry !== 'LS' && entry !== null) {
        characterSet[i] =
          typeof entry === 'string'
            ? TextEncoder.codePointsFromString(entry)[0]
            : entry
      }
    }

    // Cache variant character set
    this._variantCharacterSet[name] = characterSet
    return characterSet
  }
}