Remove Javascript console.log Automatically

| Comments

When writing a large JavaScript application, it is quite often that console.log and other debugging statements are left here and there. Obviously, at one point those statements need to be removed for the production version or even when the code needs to be checked in into the source repository. There are many different ways to do this, there exists a new tool called groundskeeper which can do this removal for you.

Written for Node.js, groundskeeper (GitHub: github.com/Couto/groundskeeper) is created by Luís Couto to handle logging removal by understanding the syntax tree of the code and deleting the relevant parts. It is not based on regular expression at all. Groundskeeper parses the code (via Esprima) and modify the syntax nodes (via falafel) associated with any logging. Beside a command-line tool, groundskeeper is also a library ready to be used in any other tools and build systems.

Using groundskeeper is pretty simple (as its documentation explained). Let’s assume we have the following filter-debug.js:

1
2
3
4
5
6
7
8
9
10
function filter(list, age) {
  var result = [];
  list.forEach(function (person) {
    if (person.name && person.age > age) {
      console.log('including', person.name);
      result.push(person);
    }
  });
  return result;
}

After its package is installed, running something like:

groundskeeper < filter-debug.js > filter.js

will give the following filter.js:

1
2
3
4
5
6
7
8
9
10
function filter(list, age) {
  var result = [];
  list.forEach(function (person) {
    if (person.name && person.age > age) {

      result.push(person);
    }
  });
  return result;
}

The line containing console.log is now a blank line. Because groundskeeper doesn’t delete the line, the processed output still has the same amount of lines of code as the original one.

How about debugger? We know that this statement may cause some problems with old web browsers. Fortunately groundskeeper can also get rid of any debugger statements in the code. In fact, you can even nuke any other custom application logger you might have. Here is a code fragment:

1
2
3
debugger
var list = filter(customers, 25);
RentalApp.Logger.print(JSON.stringify(list, null, 2));

which can be processed via:

groundskeeper -n RentalApp.Logger < rental.js

and give you the remaining output: var list = filter(customers, 25);

The biggest benefit of automatic removal is when it is combined with Git pre-commit hook so that no more manual step is necessary. This is pretty similar to the use of syntax validation trick. Here is an example of such a hook:

1
2
3
4
files=$(git diff-index --name-only --diff-filter=ACM HEAD | grep -P '\.js$')
for file in $files; do
  groundskeeper < $file > $file.tmp && mv $file.tmp $file
done

All touched *.js files will be processed via groundskeeper before they are checked in. This way, none of them will have stray console.log, debugger statements, or any other custom logger calls anymore. Thus, your repository is guaranteed to be free from debugging leftovers!

Avoiding Unwanted Scopes Creation in AngularJS

| Comments

One of the most appreciated features of AngularJs is scopes, at the same time scopes will give you nightmare if don’t avoid unwanted scopes from creating.

Preventing ng-model data scope is one of the main challenge you get quite often. While working with ng-model data, new unwanted scope can be created by ng-repeat or ng-if procedures. Let’s look at the below example

See the Pen Angular unwanted scope creation by Logesh Paul (@logeshpaul) on CodePen.

In the above example, the scope is created separately for innerScope and outerScope, so it does not share it’s data. We can handle this with single scope - One way to do this is we can use “Controller As” approach instead of using scope as a container for all data and functions.

One catchy solution is to keep everything in objects as shown is below example

See the Pen Angular avoiding unwanted scope creation by Logesh Paul (@logeshpaul) on CodePen.

Credits: http://www.jstips.co/en/angular/preventing-unwanted-scopes-creation-in-angularjs/

Let me what methods/best practices you follow to avoid unwanted scopes from creating in AngularJS.