+flow-obj-map.js

// @flow

type PipeObjMap<B,C> = <A>(A => B) => (A => C);

const pipeFn = <A,B,C>(fn1: A => B, fn2: B => C): (A => C) => (v: A) => fn2(fn1(v));

const pipeObj = <Fns: {},B,C>(fns: Fns, fn2: B => C): $ObjMap<Fns, PipeObjMap<B,C>> => {
  const res = {};

  for (const k in fns) {
    if (fns.hasOwnProperty(k)) {
      res[k] = pipeFn(fns[k], fn2);
    }
  }

  return res;
};

const dbl = (v: number): number => v * 2;

const d = {
  a: (v: string): number => +v,
  b: (v: number): number => v * 3
};

const d2 = pipeObj(d, dbl);

console.log(d2.a('23'));
console.log(d2.b(21));

.flowconfig

[ignore]

[include]

[libs]

[lints]

[options]

[strict]

package-lock.json

{
  "name": "flow-obj-map",
  "version": "1.0.0",
  "lockfileVersion": 1,
  "requires": true,
  "dependencies": {
    "babylon": {
      "version": "6.18.0",
      "resolved": "https://registry.npmjs.org/babylon/-/babylon-6.18.0.tgz",
      "integrity": "sha512-q/UEjfGJ2Cm3oKV71DJz9d25TPnq5rhBVL2Q4fA5wcC3jcrdn7+SssEybFIxwAvvP+YCsCYNKughoF33GxgycQ==",
      "dev": true
    },
    "flow-bin": {
      "version": "0.62.0",
      "resolved": "https://registry.npmjs.org/flow-bin/-/flow-bin-0.62.0.tgz",
      "integrity": "sha1-FLymaabj+VwLwMLR61XsTpjLHYM=",
      "dev": true
    },
    "flow-remove-types": {
      "version": "1.2.3",
      "resolved": "https://registry.npmjs.org/flow-remove-types/-/flow-remove-types-1.2.3.tgz",
      "integrity": "sha512-ypq/U3V+t9atYiOuSJd40tekCra03EHKoRsiK/wXGrsZimuum0kdwVY7Yv0HTaoXgHW1WiayomYd+Q3kkvPl9Q==",
      "dev": true,
      "requires": {
        "babylon": "6.18.0",
        "vlq": "0.2.3"
      }
    },
    "vlq": {
      "version": "0.2.3",
      "resolved": "https://registry.npmjs.org/vlq/-/vlq-0.2.3.tgz",
      "integrity": "sha512-DRibZL6DsNhIgYQ+wNdWDL2SL3bKPlVrRiBqV5yuMm++op8W4kGFtaQfCs4KEJn0wBZcHVHJ3eoywX8983k1ow==",
      "dev": true
    }
  }
}

package.json

{
  "name": "flow-obj-map",
  "version": "1.0.0",
  "description": "",
  "main": "+flow-obj-map.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "flow-bin": "^0.62.0",
    "flow-remove-types": "^1.2.3"
  }
}