Package Exports
- declared
This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (declared) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.
Readme
declared 
declared is a module for setting default values for optional arguments.
Actually, it is a bit more general than that. It takes a bunch of values, and simply returns the first value that is "!= undefined".
The problem it is solving is that in JavaScript the argument is considered omitted if it is either null or undefined (common convention), but there's no built-in operator for this.
The closest thing is logical or (||), but it is not quite what we want.
> '' || 'default'
'default'This module is a counterpart to @substack's defined which checks for strong equality for some reason (and does not work for nulls).
Example
// Say description is optional.
function describe(name, description) {
description = declared(description, 'coolest thing ever!');
return [name, description];
}
> describe('x', 'my description')
[ 'x', 'my description' ]
> describe('x', '')
[ 'x', '' ]
// null and undefined both stand for the default value.
> describe('x', null)
[ 'x', 'coolest thing ever!' ]
> describe('x', undefined)
[ 'x', 'coolest thing ever!' ]API
declared([value]...)
Return the first argument that is "!= undefined" (or "!= null", which is the same thing). If all arguments are undefined, just return undefined.
Equivalent chain of conditional statements:
if (value0 != null) {
return value0;
}
else if (value1 != null) {
return value1;
}
/* ... */
else if (valueN != null) {
return valueN;
}
else {
return undefined;
}Install
npm install declaredLicense
MIT