@winged/core/src/vdom/dataPoint/I18nExtension.ts

Morden webapp framekwork made only for ts developers. (UNDER DEVELOPMENT, PLEASE DO NOT USE)

import { utils } from '../../utils'
import { DataPointExtension } from './DataPointExtension'

/**
 * format :
 * {{"@some.key.name:[default text]"}}
 */
export class I18nExtension extends DataPointExtension {

  public static setMessages(messages: { [key: string]: string }) {
    this.i18nMessages = messages
    for (const id in this.translatableInstances) {
      this.translatableInstances[id].requireUpdate()
    }
  }

  public static getMessage(key: string) {
    return this.i18nMessages[key]
  }

  public static registerInstance(instance: I18nExtension) {
    const id = utils.generateId()
    this.translatableInstances[id] = instance
    return id
  }

  public static unregisterInstance(id: string) {
    delete this.translatableInstances[id]
  }
  private static translatableInstances: { [id: string]: I18nExtension } = {}
  private static i18nMessages: { [key: string]: string } = {}
  private static valueMatcher = /^@([\w.]+)(?::(.+))?$/
  private static messageTester = /@[\w.]+(?::.+)?/

  private hasI18nMsg: boolean
  private id: string

  public init(expression: string): string {
    if (I18nExtension.messageTester.test(expression)) {
      this.hasI18nMsg = true
      this.id = I18nExtension.registerInstance(this)
    }
    return expression
  }

  public onValueChange(value: string): string {
    if (this.hasI18nMsg && value[0] === '@') {
      const match = value.match(I18nExtension.valueMatcher)
      if (!match) {
        return value
      } else {
        const [key, defaultMsg] = match
        if (I18nExtension.i18nMessages[key]) {
          return I18nExtension.i18nMessages[key]
        } else if (defaultMsg) {
          console.warn(`[i18n] Can't find message for key:"${key}" using default value`)
          return defaultMsg
        } else {
          console.error(
            `[i18n] Can't find message for key:"${key}" and no default value provided, please set a default value`
          )
          return ''
        }
      }
    }
    return value
  }

  public onDestroy() {
    I18nExtension.unregisterInstance(this.id)
  }
}