flow-proxy-middleware/lib/try-require.js

> 本中间件是对http-proxy-middleware的封装，能够实现webpack的proxy写法

const cwd = process.cwd()
const resolve = require('resolve')

// attempts to first require a dep using projects cwd
// then try a normal require.
module.exports = function tryRequire (dep) {
    let fromCwd
    try {
        fromCwd = resolve.sync(dep, { basedir: cwd })
    } catch (e) {}
    if (fromCwd) {
        return require(fromCwd)
    } else {
        try {
            return require(dep)
        } catch (e) {}
    }
}