wheeyls/repeat_until.js

## repeat_until.js
/**
 * Poll until a test passes.
 * When the test returns something, (not false) pass its value to and_then
 *
 * Example:
 *   repeat_until(function() {
 *     return "some value";
 *   }).and_then(function(result) {
 *     console.log(result); // "some value"
 *   }).timeout(function() {
 *     console.log("timed out trying!");
 *   }, 5000);
 *
 * jslint sloppy: true, white: true, maxerr: 50, indent: 2, browser: true
 **/
(function(context) {
  var repeat_until = function(test, delay) {
    var done = false, me, completeFn,
      success_timer, success_callbacks = [], failure_timer, test_result, repeat;

    delay = delay !== undefined ? delay : 20;

    repeat = function() {
      var i, ii;

      test_result = test();
      if(test_result === false) {
        success_timer = window.setTimeout(repeat, delay);
      } else {
        completeFn(test_result);
      }
    };

    completeFn = function (test_result) {
      done = true;
      window.clearTimeout(failure_timer);
      for (i=0, ii = success_callbacks.length; i<ii; i+=1) {
        success_callbacks[i](test_result);
      }
    };

    me = {
      and_then: function(success) {
        if(done && test_result !== false) {
          success(test_result);
        } else {
          success_callbacks.push(success);
        }
        return me;
      },
      now: function () {
        completeFn(test_result);
      },
      timeout: function(failure, time) {
        time = time !== undefined ? time : 7000;
        failure_timer = window.setTimeout(function() {
          if(!done) {
            done = true;
            failure();
            window.clearTimeout(success_timer);
          }
        }, time);
        return me;
      }
    };

    repeat();

    return me;
  };

  context.repeat_until = repeat_until;
}(this));

## tests.html
<html>
  <head>
<script src="http://code.jquery.com/jquery-latest.js"></script>
<link rel="stylesheet" href="http://code.jquery.com/qunit/git/qunit.css" type="text/css" media="screen" />
<script type="text/javascript" src="http://code.jquery.com/qunit/git/qunit.js"></script>
<script src="repeat_until.js"></script>
    <script type="text/javascript">
      (function() {
        module("repeat_until", {
          setup: function() { },
          teardown: function() { }
        });
        test("works by itself", function() {
          var count = 0;
          repeat_until(function() { count+=1;return count; }, 0);
          ok(count === 1, "no delay, so synchronous");
        });
        asyncTest("on pass and_then is called", function() {
          var count = 0;
          repeat_until(function() {
            count+=1;
            return count === 2 ? count : false;
          }, 0).and_then(function(c) {
            start();
            equal(count, c, "value passed through to and_then");
          });
        });
        asyncTest("on fail timeout is called", function() {
          repeat_until(function() {
            return false;
          }, 0).and_then(function(c) {
            start(); ok(false, "should not have gotten here");
          }).timeout(function(c) {
            start(); ok(true, "failed as expected");
          }, 0);
        });
        asyncTest("can be triggered immediately", function() {
          repeat_until(function() {
            return false;
          }, 1000).and_then(function(c) {
            start(); ok(true, "should not have gotten here");
          }).now();
        });
        test("and_then can be checked later", function() {
          var x = repeat_until(function() {
            return true;
          });
          x.and_then(function(val) {
            ok(val, "Successfully processed");
          });
        });
        asyncTest("timeout can be applied later", function() {
          var x = repeat_until(function() {
            return false;
          }, 0);
          x.timeout(function() {
            start();
            ok(true, "Successfully applied timeout");
          }, 0);
        });
        test("works in whatever order", function() {
          repeat_until(function() {
            return true;
          }).timeout(function() {
            ok(false, "should not have timed out");
          }).and_then(function(val) {
            ok(val, "true returned from repeater");
          });
        });
        asyncTest("and_then, and_then, and_then", function() {
          expect(3);
          var count = 0;
          var poll = repeat_until(function() {
            if( ++count === 2) {
              return "completed";
            }
            return false;
          }).and_then(function(val) {
            equal("completed", val, "first callback done");
          }).and_then(function(val) {
            start();
            equal("completed", val, "second callback done");
            poll.and_then(function(val) {
              equal("completed", val, "fired immediately");
            });
          });
        });
      }());
    </script>
  </head>
  <body>
    <p>Some content.</p>
    <input type="hidden" id="mod_mgr_run_tests" value="true"/>

  <h1 id="qunit-header">QUnit example</h1>
 <h2 id="qunit-banner"></h2>
 <div id="qunit-testrunner-toolbar"></div>
 <h2 id="qunit-userAgent"></h2>
 <ol id="qunit-tests"></ol>
 <div id="qunit-fixture">test markup, will be hidden</div>
  </body>
</html>
	/**
	* Poll until a test passes.
	* When the test returns something, (not false) pass its value to and_then
	*
	* Example:
	* repeat_until(function() {
	* return "some value";
	* }).and_then(function(result) {
	* console.log(result); // "some value"
	* }).timeout(function() {
	* console.log("timed out trying!");
	* }, 5000);
	*
	* jslint sloppy: true, white: true, maxerr: 50, indent: 2, browser: true
	**/
	(function(context) {
	var repeat_until = function(test, delay) {
	var done = false, me, completeFn,
	success_timer, success_callbacks = [], failure_timer, test_result, repeat;

	delay = delay !== undefined ? delay : 20;

	repeat = function() {
	var i, ii;

	test_result = test();
	if(test_result === false) {
	success_timer = window.setTimeout(repeat, delay);
	} else {
	completeFn(test_result);
	}
	};

	completeFn = function (test_result) {
	done = true;
	window.clearTimeout(failure_timer);
	for (i=0, ii = success_callbacks.length; i<ii; i+=1) {
	success_callbacks[i](test_result);
	}
	};

	me = {
	and_then: function(success) {
	if(done && test_result !== false) {
	success(test_result);
	} else {
	success_callbacks.push(success);
	}
	return me;
	},
	now: function () {
	completeFn(test_result);
	},
	timeout: function(failure, time) {
	time = time !== undefined ? time : 7000;
	failure_timer = window.setTimeout(function() {
	if(!done) {
	done = true;
	failure();
	window.clearTimeout(success_timer);
	}
	}, time);
	return me;
	}
	};

	repeat();

	return me;
	};

	context.repeat_until = repeat_until;
	}(this));
	<html>
	<head>
	<script src="http://code.jquery.com/jquery-latest.js"></script>
	<link rel="stylesheet" href="http://code.jquery.com/qunit/git/qunit.css" type="text/css" media="screen" />
	<script type="text/javascript" src="http://code.jquery.com/qunit/git/qunit.js"></script>
	<script src="repeat_until.js"></script>
	<script type="text/javascript">
	(function() {
	module("repeat_until", {
	setup: function() { },
	teardown: function() { }
	});
	test("works by itself", function() {
	var count = 0;
	repeat_until(function() { count+=1;return count; }, 0);
	ok(count === 1, "no delay, so synchronous");
	});
	asyncTest("on pass and_then is called", function() {
	var count = 0;
	repeat_until(function() {
	count+=1;
	return count === 2 ? count : false;
	}, 0).and_then(function(c) {
	start();
	equal(count, c, "value passed through to and_then");
	});
	});
	asyncTest("on fail timeout is called", function() {
	repeat_until(function() {
	return false;
	}, 0).and_then(function(c) {
	start(); ok(false, "should not have gotten here");
	}).timeout(function(c) {
	start(); ok(true, "failed as expected");
	}, 0);
	});
	asyncTest("can be triggered immediately", function() {
	repeat_until(function() {
	return false;
	}, 1000).and_then(function(c) {
	start(); ok(true, "should not have gotten here");
	}).now();
	});
	test("and_then can be checked later", function() {
	var x = repeat_until(function() {
	return true;
	});
	x.and_then(function(val) {
	ok(val, "Successfully processed");
	});
	});
	asyncTest("timeout can be applied later", function() {
	var x = repeat_until(function() {
	return false;
	}, 0);
	x.timeout(function() {
	start();
	ok(true, "Successfully applied timeout");
	}, 0);
	});
	test("works in whatever order", function() {
	repeat_until(function() {
	return true;
	}).timeout(function() {
	ok(false, "should not have timed out");
	}).and_then(function(val) {
	ok(val, "true returned from repeater");
	});
	});
	asyncTest("and_then, and_then, and_then", function() {
	expect(3);
	var count = 0;
	var poll = repeat_until(function() {
	if( ++count === 2) {
	return "completed";
	}
	return false;
	}).and_then(function(val) {
	equal("completed", val, "first callback done");
	}).and_then(function(val) {
	start();
	equal("completed", val, "second callback done");
	poll.and_then(function(val) {
	equal("completed", val, "fired immediately");
	});
	});
	});
	}());
	</script>
	</head>
	<body>
	<p>Some content.</p>
	<input type="hidden" id="mod_mgr_run_tests" value="true"/>

	<h1 id="qunit-header">QUnit example</h1>
	<h2 id="qunit-banner"></h2>
	<div id="qunit-testrunner-toolbar"></div>
	<h2 id="qunit-userAgent"></h2>
	<ol id="qunit-tests"></ol>
	<div id="qunit-fixture">test markup, will be hidden</div>
	</body>
	</html>