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danschultz/gist:596d02d6f330e4ab7393

Created February 26, 2015 08:50
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  1. danschultz created this gist Feb 26, 2015.
    67 changes: 67 additions & 0 deletions gistfile1.dart
    View file
    Original file line number Diff line number Diff line change
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    import 'dart:async';
    import 'dart:html';
    import 'dart:math';
    import 'package:frappe/frappe.dart';

    InputElement usernameInput = querySelector("#username");
    Element usernameAvailable = querySelector("#usernameAvailable");
    InputElement fullnameInput = querySelector("#fullname");
    ButtonElement registerButton = querySelector("#register");
    Element result = querySelector("#result");

    void main() {
    var username = new Property<String>.fromStreamWithInitialValue(usernameInput.value, usernameInput.onInput.map(inputValue));
    var fullname = new Property<String>.fromStreamWithInitialValue(fullnameInput.value, fullnameInput.onInput.map(inputValue));

    var isUsernameValid = username.map((value) => value.isNotEmpty);
    var isFullnameValid = fullname.map((value) => value.isNotEmpty);
    var isUsernameAvailable = username
    .changes
    .flatMapLatest((value) => new Stream.fromFuture(fetchIsUsernameAvailable(value)));
    var isValid = isUsernameValid
    .combine(isFullnameValid, (a, b) => a && b)
    .combine(isUsernameAvailable, (a, b) => a && b)
    .asPropertyWithInitialValue(false);

    var onSubmit = new EventStream(usernameInput.onKeyUp.where(isEnterKey))
    .merge(fullnameInput.onKeyUp.where(isEnterKey))
    .merge(registerButton.onClick)
    .when(isValid);

    var onRequestRegistration = username
    .combine(fullname, (username, fullname) => register(username, fullname))
    .sampleOn(onSubmit);

    username.changes.forEach((_) => usernameAvailable.text = "");

    isUsernameAvailable
    .distinct()
    .doAction((value) => print("Username available? $value"))
    .where((value) => !value)
    .forEach((value) => usernameAvailable.text = "Sorry, username is taken");

    isValid
    .distinct()
    .doAction((value) => print("Form valid? $value"))
    .forEach((value) => registerButton.disabled = !value);

    onRequestRegistration
    .doAction((_) => print("Registering ..."))
    .asyncMap((request) => request)
    .doAction((_) => print("Registered!"))
    .forEach((_) => result.text = "Thanks, you're registered!");
    }

    Future<bool> fetchIsUsernameAvailable(String username) {
    return new Future.delayed(randomDelay(), () => username.length % 2 == 0);
    }

    Future<bool> register(String username, String fullname) {
    return new Future.delayed(randomDelay() * 4, () => true);
    }

    Duration randomDelay() => new Duration(milliseconds: new Random().nextInt(500) + 500);

    String inputValue(Event event) => event.target.value;

    bool isEnterKey(KeyboardEvent event) => event.keyCode == 13;