apiMock.js

const fs = require("fs");
const path = require("path");
const chokidar = require("chokidar");
const { pathToRegexp } = require("path-to-regexp");

const mocker = {};
const cacheUrlInFile = {};

// “？：”非获取匹配，匹配冒号后的内容但不获取匹配结果，不进行存储供以后使用。
// pathToRegexp('/api/users/:id') => /^\/api\/users(?:\/([^\/#\?]+?))[\/#\?]?$/i
const getMockerKey = (url, method) => {
  return Object.keys(mocker).find((key) => {
    return pathToRegexp(key.replace(new RegExp(`^${method} `, "i"), "")).exec(
      url
    );
  });
};

module.exports.apiMock = (app, dir) => {
  app.all("/*", (req, res, next) => {
    const { path, method } = req;
    const mockerKey = getMockerKey(path, method);
    if (mockerKey && mocker[mockerKey]) {
      return res.send(mocker[mockerKey]);
    }
    next();
  });
  chokidar.watch(dir).on("all", (event, curPath) => {
    if (event === "unlink") {
      console.log("删除mock文件：", curPath);
      const toDeleteArr = cacheUrlInFile[curPath];
      toDeleteArr.forEach((item) => {
        delete mocker[item];
      });
    } else if (["add", "change"].includes(event)) {
      if (fs.statSync(curPath).isFile()) {
        console.log(`${event === "add" ? "新增" : "修改"}mock文件：`, curPath);
        try {
          delete require.cache[path.resolve(curPath)];
          const module = require(curPath);
          Object.assign(mocker, module);
          Object.assign(cacheUrlInFile, {
            [curPath]: Object.keys(module),
          });
        } catch (err) {
          console.warn(`读取mock文件${curPath}失败，请按照规则刷新文件内容`);
        }
      }
    }
  });
};