Created
March 12, 2018 11:04
-
-
Save frontsideair/67b3b93df9d8796b94388837c0143b6e to your computer and use it in GitHub Desktop.
Type-safe form validation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// @flow | |
import React, { Component } from "react" | |
import { isIP, isURL, isEmail, isPort } from "validator" | |
import { allValid, getErrors } from "./validation" | |
import { makeAPICall } from "./api" | |
// a flat data structure for viewing in the UI | |
type Inputs = { | |
hasAuth: boolean, | |
username: string, | |
password: string | |
} | |
// a nested data structure received from and sent to the API | |
type Auth = { | |
username: string, | |
password: string, | |
} | null | |
function fromInputs({ hasAuth, username, password }: Inputs): Auth { | |
return hasAuth ? { username, password } : null | |
} | |
function toInputs(auth: Auth): Inputs { | |
return auth === null ? { username: "", password: "" } : auth | |
} | |
type Props = { | |
auth: Auth | |
} | |
type State = { | |
inputs: Inputs | |
} | |
class Form extends Component<Props, State> { | |
state = { | |
inputs: toInputs(this.props.auth) | |
} | |
handleAuthChange = e => {} | |
handleUsernameChange = e => {} | |
handlePasswordChange = e => {} | |
render() { | |
const { hasAuth, username, password } = this.state.inputs | |
const validators = { | |
username: username => (hasAuth && username === "") ? "Username can't be empty" : null, | |
password: password => (hasAuth && password.length < 6) ? "Password must be at least 6 characters" : null | |
} | |
const errors = getErrors(this.state.inputs, validators) | |
return ( | |
<form onSubmit={e => makeAPICall(fromInputs(this.state.inputs))}> | |
<input type="checkbox" checked={hasAuth} onChange={this.handleAuthChange} /> | |
<input type="text" value={username} onChange={this.handleUsernameChange} disabled={!hasAuth} /> | |
<input type="password" value={password} onChange={this.handlePasswordChange} disabled={!hasAuth} /> | |
<button type="submit" disabled={!allValid(errors)}>Submit</button> | |
</form> | |
) | |
} | |
} |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// @flow | |
import { evolve, pick, keys } from "ramda" | |
type Err = null | string | |
type Errors<T> = { [$Keys<T>]: Err } | |
type Validator = string => Err | |
type Validators<T> = { [$Keys<T>]: Validator } | |
export function allValid<T>(errors: Errors<T>): boolean { | |
return Object.values(errors).every(err => err === null) | |
} | |
export function getErrors<T>(state: T, validators: Validators<T>): Errors<T> { | |
const interestedState = pick(keys(validators), state) | |
return evolve(validators, interestedState) | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment