[monkeyfacebag]

> In those expressions, you have access to Javascript code

Just to clarify, double curly expressions in Angular, {{ }}, are "JS-like", basically a subset of JS + filter syntax. One goal of the expression syntax is to prevent a lot of app logic being stuck into the template itself, so the subset of JS is fairly minimal, but this is by design. This also means that the expressions are not eval()'d. Instead, they are parsed with Angular's $parse service.

See: http://docs.angularjs.org/guide/expression

[lukifer]

I'm curious about the speed hit of these parsed expressions. Do you know if they are pre-compiled into anonymous functions, or if they are parsed on the fly?

[snprbob86]

See: https://github.com/angular/angular.js/blob/9480136d9f062ec4b...

Looks like they are never interpreted, but there are (at least) two different compilation strategies: 1) Anonymous function with a loop 2) Fully compiled Function constructed via JavaScript source with the loop unrolled In general, this bit of code seems to be optimized to a crazy degree.

It's also worth noting that the "filters" part of the expression is maintained as a pipeline in an array, since filters may inform bidiectional binding behavior.

[aswanson]

Was thinking the same thing. My guess is on-the-fly parsing.