Assert Exists
A package for consistently asserting if a variable exists.
Usage
-
Install.
npm install assert-exists --save
-
Use it.
var a = ; var errorMsg = a; { a; a;}
Definition
.exists(value, errorMessage, *type)
- Checks to see if value is not null, AND
typeof
type (if it's provided), otherwise throwsAssertionError: "errorMessage"
.
- Checks to see if value is not null, AND
.msg(packageString)
- Returns a function that takes one argument and returns a string like:
"ERROR: Expected {1} to be passed into {packageString}."
Why
When passing configs into constructors, I ran into a problem where the same code was copied and pasted lots of times. That was annoying, verbose and error prone. It looked like this:
{ ; ; thisenabled = configsenabled; ; ;}
This sucks. So, I made the package to constrict my ability to mess this stuff up, and take away some of the copy-pasta incentive.
Now we have one function to check if it exists, and one to get an error message. Simple.
a.exists(finished, a.msg('README')('finished'), 'bool');