@voerkai18n/runtime/src/scope/mixins/translate.ts

runtime of voerkai18n

import { isMessageId } from "@/utils/isMessageId";
import { isFunction } from "flex-tools/typecheck/isFunction";
import { isNumber } from "flex-tools/typecheck/isNumber";
import { isPlainObject } from "flex-tools/typecheck/isPlainObject";
import type { VoerkaI18nScope } from "..";
import type {
  VoerkaI18nTranslateVars,
  VoerkaI18nTranslateOptions,
  VoerkaI18nLanguageMessages,
} from "@/types";

export class TranslateMixin {
  /**
   * 根据值的单数和复数形式，从messages中取得相应的消息
   *
   * @param {*} messages  复数形式的文本内容 = [<=0时的内容>，<=1时的内容>，<=2时的内容>,...,<>=N的内容>]
   * @param {*} value
   */
  private _getPluraMessage(
    this: VoerkaI18nScope,
    messages: string | string[],
    value: number
  ) {
    try {
      if (Array.isArray(messages)) {
        return messages.length > value
          ? messages[value]
          : messages[messages.length - 1];
      } else {
        return messages;
      }
    } catch {
      return Array.isArray(messages) ? messages[0] : messages;
    }
  }
  private _getPluraValue(args: any): [number | null, any[]] {
    let pluraValue: number | null = null; // 复数值
    let vars: any[] = []; // 插值变量列表
    // 1. 预处理变量:  复数变量保存至pluralVars中 , 变量如果是Function则调用
    if (isPlainObject(args)) {
      // 字典插值
      const dictVars: Record<string, any> = args;
      for (const [name, value] of Object.entries(dictVars)) {
        if (isFunction(value)) {
          try {
            dictVars[name] = value();
          } catch {
            dictVars[name] = value;
          }
        }
        const isNum: boolean = typeof dictVars[name] === "number"; // 以$开头的视为复数变量，记录下来
        if ((pluraValue == null && isNum) || (name.startsWith("$") && isNum)) {
          pluraValue = dictVars[name];
        }
      }
      vars = [dictVars];
    } else if (Array.isArray(args)) {
      // 位置插值
      vars = args.map((arg) => {
        try {
          arg = isFunction(arg) ? arg() : arg;
          if (isNumber(arg) && !pluraValue) pluraValue = parseInt(arg); // 约定：位置参数中以第一个数值变量作为指示复数变量
        } catch {
          return String(arg);
        }
        return arg;
      });
    } else if (args !== undefined) {
      // 单个插值
      pluraValue = isNumber(args) ? parseInt(args) : 0;
      vars = [args];
    }
    return [pluraValue, vars];
  }

  /**
   * 翻译组件
   *
   */
  protected _getTranslateComponent(this: VoerkaI18nScope): any {
    if (!this._translateComponent) {
      const builder = this.options.component || this.appScope.options.component;
      if (typeof builder === "function") {
        this._translateComponent = builder.call(this, this);
      } else {
        this._translateComponent = () => {};
        this.logger.warn("No translate component builder configured");
      }
    }
    return this._translateComponent;
  }
  protected _getTranslateTransformer(this: VoerkaI18nScope): any {
    if (!this._translateTransformer) {
      const builder = this.options.transform || this.appScope.options.transform;
      if (typeof builder === "function") {
        this._translateTransformer = builder.call(this, this);
      }
    }
    return this._translateTransformer;
  }

  private _getActiveMessages(
    this: VoerkaI18nScope,
    language: string
  ): VoerkaI18nLanguageMessages {
    const messages = this.messages[language];
    if (typeof messages === "function") {
      this.logger.warn(
        `When the t function specifies the language <${language}> , only synchronized language packs can be used`
      );
      return this.activeMessages;
    }
    return (this.messages as any)[language] as VoerkaI18nLanguageMessages;
  }
  translate<R = string>(
    this: VoerkaI18nScope,
    message: string,
    vars?: VoerkaI18nTranslateVars,
    options?: VoerkaI18nTranslateOptions
  ): R {
    if (typeof message !== "string") {
      this.logger.debug(
        `failed to translate message:${message},it is not a string`
      );
      return "" as R;
    }
    const activeLanguage = options?.language || this.activeLanguage;
    const activeMessages = this._getActiveMessages(activeLanguage);

    // 为什么样要转义换行符？因为在translates/*.json中key不允许换行符存在，需要转义为\\n，这里需要转回来
    message = message.replace(/\n/g, "\\n");
    // 如果内容是复数，则其值是一个数组，数组中的每个元素是从1-N数量形式的文本内容
    let result: any = message;
    if (!(typeof message === "string")) return message;
    const finalArgs =
      vars === undefined ? [] : isFunction(vars) ? vars() : vars;
    try {
      if (isMessageId(message)) {
        // 如果是数字id,
        result = (activeMessages as any)[message] || message;
      } else {
        const msgId = this.idMap[message];
        // 语言包可能是使用idMap映射过的，则需要转换
        result = (activeMessages[msgId] ||
          activeMessages[message] ||
          message) as string | string[];
      }
      const [pluraValue, vars] = this._getPluraValue(finalArgs);
      // 2. 处理复数
      // 经过上面的处理，content可能是字符串或者数组
      // content = "原始文本内容" || 复数形式["原始文本内容","原始文本内容"....]
      // 如果是数组说明要启用复数机制，需要根据插值变量中的某个变量来判断复数形式
      if (Array.isArray(result) && result.length > 0) {
        // 如果存在复数命名变量，只取第一个复数变量
        if (pluraValue !== null) {
          // 启用的是位置插值
          result = this._getPluraMessage(result, pluraValue!);
        } else {
          // 如果找不到复数变量，则使用第一个内容
          result = result[0];
        }
      }
      // 如果没有传入插值变量，则直接返回
      if (finalArgs.length === 0) result as string;
      // 进行插值处理
      result = this.interpolator.replace(result as string, ...vars);

      if (isFunction(this.options.onTranslated)) {
        result = this.options.onTranslated(result);
      }
      if (this._translateTransformer && options?.transform) {
        result = this._translateTransformer(result, vars, options);
      }
    } catch (e: any) {
      this.logger.error(`翻译失败：${e.stack}`);
    }
    return result as R;
  }
}