generatePath

generatePath函数主要调用path-to-regexp中的compile实现，compile的作用是根据路径匹配规则产生一个路径生成函数，如下代码所示：

const toPath = pathToRegexp.compile('/user/:id')

toPath({ id: 123 }) //=> "/user/123"
toPath({ id: 'café' }) //=> "/user/caf%C3%A9"
toPath({ id: '/' }) //=> "/user/%2F"

toPath({ id: ':/' }) //=> "/user/%3A%2F"
toPath({ id: ':/' }, { encode: (value, token) => value }) //=> "/user/:/"

const toPathRepeated = pathToRegexp.compile('/:segment+')

toPathRepeated({ segment: 'foo' }) //=> "/foo"
toPathRepeated({ segment: ['a', 'b', 'c'] }) //=> "/a/b/c"

const toPathRegexp = pathToRegexp.compile('/user/:id(\\d+)')

toPathRegexp({ id: 123 }) //=> "/user/123"
toPathRegexp({ id: '123' }) //=> "/user/123"
toPathRegexp({ id: 'abc' }) //=> Throws `TypeError`.

generatePath(path = "/", params = {}) 根据传入的path以及params产生一个路径，当传入的path为根目录"/"时，直接返回"/"。如下例所示：

console.log(generatePath('/user/:id',{id:123}),)    
//输出为：  "/user/123"

源码

import pathToRegexp from "path-to-regexp";

const cache = {};
const cacheLimit = 10000;
let cacheCount = 0;

function compilePath(path) {
  if (cache[path]) return cache[path];

  const generator = pathToRegexp.compile(path);

  if (cacheCount < cacheLimit) {
    cache[path] = generator;
    cacheCount++;
  }

  return generator;
}

/**
 * Public API for generating a URL pathname from a path and parameters.
 */
function generatePath(path = "/", params = {}) {
  return path === "/" ? path : compilePath(path)(params, { pretty: true });
}

export default generatePath;