Expose and Require
Adds "module.exports" to a file, exposing:
- globally defined variables (either with
const
,let
orvar
); - globally declared functions with "function" keyword;
- classes declared with
class
keyword (including child classes withextends
);
Updated file is then saved to the target path and require
d.
If target or source path does not exist or the file can't be read or
written, the module will attempt to resolve the issues.
WARNING The module is asynchronous, use async
/ await
or promises to avoid race conditions.
Basic usage
exposeAndRequire
function accepts three parameters:
- Path to the source file (required)
- Path to the target folder
- Options object, specifying actions / additional parameters:
color
colorize log output (using color escape sequences)exposeOnly
forces module to returnnull
and do notrequire
exposed filegrep
each line will be matched against and performed replacements on accordinglylog
redirects logging output of the module (see logging ):- to a file if path is given
- to a stream if given a
Stream
require
output file will be prepended withrequire
statementsuse
root to resolve against for required modules, can be either:root
paths are relative to"."
defaultcwd
paths are relative toprocess.cwd()
dynamicmodule
paths are relative to module folder
const ER = require('expose-require'); ER .exposeAndRequire('lib/index.js','test',{ require: { 'fs': 'fs', '{ someFunc }': 'someModule' }, grep: [{ match: /(\d+)/, replace: '$1$1' }], use: "module" }) .then(module => { //do stuff; });
Usage with source path only
You can omit both the target path and opions, in which case the file will be created in the root
directory (passing an empty string as the second agrument results is treated the same way):
const { exposeAndRequire } = require('expose-require'); //inside async functionconst someModule = await exposeAndRequire('test/test.js'); //with empty stringconst yummy = await exposeAndRequire('dinner/steak.js',''); //do stuff;
Exposing classes
Given a class or a child class declaration,
the module will add it to the current module.exports
.
class BaseClassLine {}class BaseClass { constructor() { }} //tabulated declaration class BaseClassTabbed { constructor() { } } //spaced declaration class BaseClassSpaced { constructor() { } } class ChildClassLine extends BaseClass {}class ChildClass extends BaseClass { constructor() { }}
exposes:
module.exports = exports = { BaseClassLine, BaseClass, BaseClassTabbed, BaseClassSpaced, ChildClassLine, ChildClass};
Exposing global variables
Given a variable declared in a global scope,
the module will add it to module.exports
regardless of keyword used: const
, let
, or var
.
const constVar = () => console.warn('Be warned!'); let letVar = function () { const rand = Math.floor(Math.random() * 2); const mood = new Map() .set(0, () => 'Sometimes I feel blue') .set(1, () => 'But other times I cheer!'); return mood.get(rand);}; var varVar = 42;
exposes:
module.exports = exports = { constVar, letVar, varVar};
Nested declarations
As of 1.3.0 the module ignores nested declarations. For example, given a source file:
const functionWithNestedFuncions = function () { function nested() { const inner = 'This should be unreachable'; } }
its module.exports
will not expose nested
function or inner
variable:
module.exports = exports = { functionWithNestedFuncions};
require
sources
Overriding To require a module without relation to target path, you can prefix the path with [relation]::
,
where relation
is one of the use
option values.
In the example below, without root::
, path to required coolModule
would be resolved as [module folder]/mocks/coolModule.js
, instead, it is resolved as [project root]/coolModule.js
:
const awesomeModule = await exposeAndRequire('pathToModule','mocks',{ require: { "{ doCool }" : "root::coolModule.js" }, use: "module"});
Caching
Since Node.js caches modules in require.cache
object, right before the exposed module is required, module cache is cleared (only the exposed entry will be deleted) to ensure the module is reloaded.
Side note: although the module will clear output cache, make sure you clear parent module cache if watching source files for changes.
Fallbacks
If any path in exposure lifecycle does not exist, it will be created. If a folder is missing, it will be created recursively. If a file is missing, it will be created, as well as any folder not existing in path (even if this is a source file).
Logging
By default, the module outputs status messages on stdout
using chalk
. If you intend to save or process logs, remember to remove colour escape sequences.
[RESOLVED] Created source: mocks/no-such-file.js success
[EXPOSED] test/source/tested.js => test/mocks
[FAILED] Could not process file
The module can redirect logging output for you if you need to export to a file or send to logging service (see log
and color
options).
Versions
Current version is 1.3.5
Version | Features | Squashed 🐞 |
---|---|---|
1.0.0 | Initial feature set | - |
1.1.0 | Added "mute", "log" and "color" options | Output folder location issues |
1.2.0 | Added module cache clearing | Folders with spaces escaping |
1.3.0 | Nested declarations are ignored | - |
1.3.3 | - | Edge case of "} else if {}" correctly decreases nestedness |
1.3.4 | Added `exposeOnly` option Added path validation | - |