dist/vendor.js
function find(predicate, thisArg) {
	    if (typeof predicate !== 'function') {
	        throw new TypeError('predicate is not a function');
	    }
	    return this.lift(new FindValueOperator(predicate, this, false, thisArg));
	}
function find(predicate, thisArg) {
	    if (typeof predicate !== 'function') {
	        throw new TypeError('predicate is not a function');
	    }
	    return this.lift(new FindValueOperator(predicate, this, false, thisArg));
	}
function find ( predicate , thisArg ) { if ( typeof predicate !== 'function' ) { throw new TypeError ( 'predicate is not a function' ) ; } return this . lift ( new FindValueOperator ( predicate , this , false , thisArg ) ) ; }
Emits only the first value emitted by the source Observable that meets some
condition.

<span class="informal">Finds the first value that passes some test and emits
that.</span>

<img src="./img/find.png" width="100%">

`find` searches for the first item in the source Observable that matches the
specified condition embodied by the `predicate`, and returns the first
occurrence in the source. Unlike {@link first}, the `predicate` is required
in `find`, and does not emit an error if a valid value is not found.

@example <caption>Find and emit the first click that happens on a DIV element</caption>
var clicks = Rx.Observable.fromEvent(document, 'click');
var result = clicks.find(ev => ev.target.tagName === 'DIV');
result.subscribe(x => console.log(x));

@see {@link filter}
@see {@link first}
@see {@link findIndex}
@see {@link take}

@param {function(value: T, index: number, source: Observable<T>): boolean} predicate
A function called with each item to test for condition matching.
@param {any} [thisArg] An optional argument to determine the value of `this`
in the `predicate` function.
@return {Observable<T>} An Observable of the first item that matches the
condition.
@method find
@owner Observable
Emits only the first value emitted by the source Observable that meets some condition .