leadfoot/helpers/pollUntil
(require("leadfoot/helpers/pollUntil"))(poller: function|string, argsopt: Array.<any>, timeoutopt: number, pollIntervalopt: number): function
A leadfoot/Command helper that polls for a value within the client environment until the value exists or a timeout is reached.
Parameters
| Name | Type | Attributes | Description |
|---|---|---|---|
poller |
function|string |
The poller function to execute on an interval. The function should return |
|
args |
Array.<any> | optional |
An array of arguments to pass to the poller function when it is invoked. Only values that can be serialised to JSON, plus leadfoot/Element objects, can be specified as arguments. |
timeout |
number | optional |
The maximum amount of time to wait for a successful result, in milliseconds. If not specified, the current
|
pollInterval |
number | optional |
The amount of time to wait between calls to the poller function, in milliseconds. If not specified, defaults to 67ms. |
Returns
A leadfoot/Command#then callback function that, when called, returns a promise that resolves to the value returned by the poller function on success and rejects on failure.
Examples
var Command = require('leadfoot/Command');
var pollUntil = require('leadfoot/helpers/pollUntil');
new Command(session)
.get('http://example.com')
.then(pollUntil('return document.getElementById("a");', 1000))
.then(function (elementA) {
// element was found
}, function (error) {
// element was not found
});var Command = require('leadfoot/Command');
var pollUntil = require('leadfoot/helpers/pollUntil');
new Command(session)
.get('http://example.com')
.then(pollUntil(function (value) {
var element = document.getElementById('a');
return element && element.value === value ? true : null;
}, [ 'foo' ], 1000))
.then(function () {
// value was set to 'foo'
}, function (error) {
// value was never set
});