@a-la/import
v1.12.0
Published
RegExp rules to transpile import statements into require calls (used in ÀLaMode).
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@a-la/import
@a-la/import
is a a set of rules for alamode
to transpile import
statements into require
calls in Node.JS.
ÀLaMode is a RegExp-based transpiler which works faster than AST-based transpilers such as @babel
, has no dependencies and occupies less disk space.
yarn add @a-la/import
Table Of Contents
API
The ÀLaImport is the default export and an array containing a sequence of rules for Replaceable.
import ÀLaImport from '@a-la/import'
ÀLaImport
Sequence
The rule set exported as an array by ÀLaImport
has multiple regexes and replacer functions to match all possible cases. The replacer functions expect to see the markers
property on the context, which is set by alamode
to access cut out strings. The transform can be run using @a-la/context
which is a lightweight version of alamode
which mimics its stream functionality.
/* yarn example/ */
import ÀLaContext from '@a-la/context'
import ÀLaImport from '@a-la/import'
const STRING = `import aLaMode from 'alamode'
import ALaImport from "@a-la/import"
import App from 'koa'
import test from './test'
`
;(async () => {
const context = new ÀLaContext(__filename)
context.setConfig({
import: {
alamodeModules: ['alamode', '@a-la/import'],
},
})
const { result } = await context.stream(ÀLaImport, STRING)
console.log(result)
})()
const aLaMode = require('alamode');
const ALaImport = require("@a-la/import");
let App = require('koa'); if (App && App.__esModule) App = App.default;
const test = require('./test');
Options
The transform accepts a number of options via the .alamoderc
.
- The replacement option is used to substitute the name or path of an imported module.
{ "env": { "test-build": { "import": { "replacement": { "from": "^((../)+)src", "to": "$1build" } } } } }
- The esCheck option is used to always enforce the
if (mod.__esModule)
check — by default, this check is switched off for local imports, but is added when requiring external packages to make it compatible with Babel and TypeScript.{ "env": { "test-build": { "import": { "esCheck": "always", } } } }
- The alamodeModules array contains packages known to be compiled with ÀLAMode, or traditional packages that didn't use Babel for compilation, so that the
if (mod.__esModule)
is not required.
If esCheck
is not set, and alamodeModules
does not contain the module that is being imported, the transform will attempt to find its package.json file, and see if it has the alamode
property set to true, in which case no esCheck will be appended.
Output Example
The set of rules changes import
to require
statements. When importing a default export from a module, a check will included to see if it was transpiled with Babel
which is indicated by the presence of the __esModule
property, and if it was, then the default
property is reassigned to the variable.
import aLaMode from 'alamode'
import Koa from "koa"
import { methodA, methodB } from 'alamode'
import { methodC, methodD as aliasD } from 'alamode'
import defaultALaMode, {
methodE, methodF,
} from 'alamode'
import def, * as tests from './tests'
const aLaMode = require('alamode');
let Koa = require("koa"); if (Koa && Koa.__esModule) Koa = Koa.default;
const { methodA, methodB } = require('alamode');
const { methodC, methodD: aliasD } = require('alamode');
const defaultALaMode = require('alamode'); const {
methodE, methodF,
} = defaultALaMode;
const tests = def = require('./tests');
Lines Preservation
The transform will attempt to preserve lines as they are for easier generation of source maps by alamode
. In future, this might change.
Named Imports
The named imports are only changed to replace as
into :
, otherwise the destructuring syntax is the same as for imports themselves.
import { test, test2,
test3 as alias3 }
from 'package'
const { test, test2,
test3: alias3 }
= require('package');
Named & Default
When there is a default import along with named once, the line numbers will be respected.
import def, {
test, test2,
test3 as alias3,
test4
as
alias4,
}
from
'package'
let def = require('package'); const {
test, test2,
test3: alias3,
test4
:
alias4,
}
=
def; if (def && def.__esModule) def = def.default;
Checklist
- [x]
import defaultExport from "module-name"
- [x]
import * as name from "module-name";
- [x]
import { export } from "module-name";
- [x]
import { export as alias } from "module-name";
- [x]
import { export1 , export2 } from "module-name";
- [x]
import { export1 , export2 as alias2 , [...] } from "module-name";
- [x]
import defaultExport, { export [ , [...] ] } from "module-name";
- [x]
import defaultExport, * as name from "module-name";
- [ ]
import "module-name";
- [ ]
var promise = import(module-name);
TODO
- [ ] Better
from 'package'
handling when matchers' logic is updated in therestream
.