Angular js How does eval work and why is it different from vanilla eval

Question

I was curious about the  scope  eval you so often see in directives  so I checked out the source and found the following in rootScope js      eval  function expr  locals        return  parse expr  this  locals           parse appears to be defined by ParseProvider in parse js  which appears to define some kind of mini-syntax of its own  the file is 900 lines long    My questions are    What exactly is  eval doing   Why does it need its own mini parsing language  Why isn t plain old JavaScript eval being used

User · Answer

From the test   it  should allow passing locals to the expression   inject function  rootScope      expect  rootScope  eval  a 1    a  2    toBe 3       rootScope  eval function scope  locals        scope c   locals b   4        b  3      expect  rootScope c  toBe 7          We also can pass locals for evaluation expression

User · Answer

I think one of the original questions here was not answered  I believe that vanilla eval   is not used because then angular apps would not work as Chrome apps  which explicitly prevent eval   from being used for security reasons

User · Answer

eval and  parse don t evaluate JavaScript  they evaluate AngularJS expressions  The linked documentation explains the differences between expressions and JavaScript   Q  What exactly is  eval doing  Why does it need its own mini parsing language   From the docs      Expressions are JavaScript-like code snippets that are usually placed in bindings such as    expression     Expressions are processed by  parse service    It s a JavaScript-like mini-language that limits what you can run  e g  no control flow statements  excepting the ternary operator  as well as adds some AngularJS goodness  e g  filters    Q  Why isn t plain old javascript  eval  being used   Because it s not actually evaluating JavaScript  As the docs say      If     you do want to run arbitrary JavaScript code  you should make it a controller method and call the method  If you want to eval   an angular expression from JavaScript  use the  eval   method    The docs linked to above have a lot more information

[angularjs] Angular.js: How does $eval work and why is it different from vanilla eval?

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