read-env
v2.0.0
Published
Transform environment variables into JSON object with sanitized values.
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read-env
Transform environment variables into JSON object with sanitized values.
See docs for previous version v1.3.x.
Main purpose of this library is to allow developers to configure their applications with environment variables. See: a use case example.
What's New with v2.x 🚀
- Migrated to Typescript, Yay! 🎉
- Simplified API
- With new
separator
option,nested object constructions are possible. - New
source
option allows you to use other objects, other thanprocess.env
Migrating from v1.x to v2.x
default
export is deprecated. Please use named exportreadEnv
as below:
const { readEnv } = require('read-env');
// Or
import { readEnv } from 'read-env';
// Or in browser
window.readEnv('EXAMPLE');
parse
option was renamed assanitize
.transformKey
option was renamed asformat
.- Deprecated options:
ignoreInvalidJSON
,prefix
,filter
,
Install
npm install --save read-env
or
yarn add read-env
Basic Usage
Let's say you have some environment variables starting with prefix "EXAMPLE_" like below:
EXAMPLE_OBJECT='{"prop": "value"}'
EXAMPLE_ARRAY='[1,2,3, "string", {"prop": "value"}, 5.2]'
EXAMPLE_INVALID_OBJECT='{"prop": }"value"}'
EXAMPLE_INVALID_ARRAY='[1,2,3, "string", ]{"prop": "value"}, 5.2]'
EXAMPLE_TRUE='true'
EXAMPLE_FALSE='false'
EXAMPLE_INT='5'
EXAMPLE_NEGATIVE_INT='-11'
EXAMPLE_FLOAT='5.2456'
EXAMPLE_NEGATIVE_FLOAT='-2.4567'
EXAMPLE_INT_ZERO='0'
EXAMPLE_FLOAT_ZERO='0.00'
EXAMPLE_NEGATIVE_INT_ZERO='-0'
EXAMPLE_NEGATIVE_FLOAT_ZERO='-0.00'
EXAMPLE_STRING='example'
EXAMPLE_DEEP__OBJECT__PROPERTY='value'
app.js
import { readEnv } from 'read-env';
const result = readEnv('EXAMPLE');
console.log(result);
Result:
{
"object": { "prop": "value" },
"array": [1, 2, 3, "string", { "prop": "value" }, 5.2],
"invalidObject": "{\"prop\": }\"value\"}",
"invalidArray": "[1,2,3, \"string\", ]{\"prop\": \"value\"}, 5.2]",
"true": true,
"false": false,
"int": 5,
"negativeInt": -11,
"float": 5.2456,
"negativeFloat": -2.4567,
"intZero": 0,
"floatZero": 0,
"negativeIntZero": -0,
"negativeFloatZero": -0,
"string": "example",
"deep": {
"object": {
"property": "value"
}
}
}
API
readEnv(prefix?: string, options: ReadEnvOptions = {})
Input:
prefix
(type:string
, default:undefined
): filters environment variables by prefixoptions
(type:ReadEnvOptions
, default:{}
): options object to change function's behaviour
Returns: object
(type: Record<string,any>), returns the instance, so add methods are chainable.
Options
Default Options:
{
"source": process.env,
"format": "camelcase",
"separator": "__",
"sanitize": {
"object": true,
"array": true,
"bool": true,
"int": true,
"float": true
},
"includePrefix": false
}
options.source
- Type:
object
- Default:
process.env
The source object that will be filtered, sanitized and formatted.
Type Signature:
interface Source {
[key: string]: string | undefined;
}
options.format
- Type:
boolean | string | function
- Default:
camelcase
Format environment variable name.
It's value can be:
- a
boolean
, if set tofalse
, formatting is disabled - a
string
, one of whichcamelcase
,pascalcase
,lowercase
,uppercase
- a
function
, with(rawVarName: string) => string
type signature
options.separator
- Type:
boolean | string
- Default:
__
Allows you construct nested objects from environment variable name.
- If set to
false
, constructing nested objects is disabled
Example:
const { readEnv } = require('read-env');
const testInput = {
EXAMPLE_DEEP__OBJECT_PROPERTY1: 'value1',
EXAMPLE_DEEP__OBJECT_PROPERTY2: 'value2',
};
const result = readEnv('EXAMPLE', {
source: testInput,
});
console.log(result);
Result:
{
"deep": {
"object": {
"property1": "value1",
"property2": "value2"
}
}
}
options.sanitize
- Type:
boolean | object
, - Default:
{}
Sanitize object consists of following properties which is used to
object
(type: bool, default: true): sanitize stringified objectvalue must be valid JSON input, see: JSON.parse.
array
(type: bool, default: true): sanitize stringified arrayvalue must be valid JSON input, see: JSON.parse.
int
(type: bool, default: true): sanitize numbers into integervalue must be consist of only digits.
float
(type: bool, default: true): sanitize numbers into floatvalue must be consist of only digits with decimal point.
bool
(type: bool, default: true): sanitize value into booleanvalue must have case insensitive match with "true" or "false".
options.includePrefix
- Type:
boolean
- Default:
false
If set to true, keeps the given prefix in property names.
Use Case Example
In past, I used Nightmare for acceptance testing and tests had different configurations based on the environment they were running on.
So, I simply used read-env, and nightmare is fully configurable with environment variables :)
import Nightmare from 'nightmare';
import { readEnv } from 'read-env';
const nightmareConfig = readEnv('MY_NIGHTMARE');
const nightmare = Nightmare(nightmareConfig);
Instead of writing code like below:
import Nightmare from 'nightmare';
const nightmare = Nightmare({
show: process.env.MY_NIGHTMARE_SHOW || false,
width: process.env.MY_NIGHTMARE_WIDTH || 1280,
height: process.env.MY_NIGHTMARE_HEIGHT || 720,
typeInterval: process.env.MY_NIGHTMARE_TYPE_INTERVAL || 50,
//... other properties go forever
});
Contribution
As always, I'm open to any contribution and would like to hear your feedback.
Just an important reminder:
If you are planning to contribute to any open source project, before starting development, please always open an issue and make a proposal first. This will save you from working on features that are eventually going to be rejected for some reason.
LICENCE
MIT (c) 2020 Mehmet Yatkı