config-expander

Expands expressions in config files

example

file.js

``js
import { expand } from "config-expander";

// expanding hole expressions at the value position (result key is a number)
expand({ key: "${value + 1}" }, { constants: { value: 77 } }).then(r =>
console.log(JSON.stringify(r))
);

// calculate port numbers
expand({ constants: { base: 10000 }, http: { port: "${base + 1}" } }).then(r =>
console.log(JSON.stringify(r))
);

// load config from file
expand("${include('tests/fixtures/other.json')}").then(r =>
console.log(JSON.stringify(r))
);
`

Output

`json
{ "key" : 78 }
{ "constants": { "base": 10000 }, "http": { "port": 10001 }}
{ "key": "value from other" }
`

Examples

read config file (json)

`js
const configuration await expand("${include('" + '/path/to/the/config.json' + "')}")
`

load key file

`json
{
"ca": "${document(os.home + '/ca.pem')}"
}
`

calculate port numbers

`json
{
"http-port": "${base + 0}",
"https-port": "${base + 1}"
}
`

conditions

`json
{
"copy-cmd": "${os.platform == 'win32' ? 'copy' : 'cp'}"
}
`

API

$3

* defaultConstants
* Properties
* expand
* Parameters
* Context
* Properties
* Value
* Properties
* Apply
* Parameters
* ConfigFunction
* Properties
* functions
* include
* Parameters
* replace
* Parameters
* toUpperCase
* Parameters
* toLowerCase
* Parameters
* split
* Parameters
* encrypt
* Parameters
* decrypt
* Parameters
* spawn
* Parameters
* merge
* Parameters

defaultConstants

Predefined constants

Type: Object

$3

* env Object environment variables from process.env
* os Object os module
* basedir string filesystem configuration start point

expand

Expands expressions in a configuration object

$3

* config Object config source
* options Object the options

* options.constants Object additional constants
* options.default Object default configuration
* options.functions Object additional functions

Returns Promise<Object> resolves to the expanded configuration

Context

Type: Object

$3

* constants Object

* constants.basedir string
* constants.env Object
* constants.os string
* functions Object

Value

Type: Object

$3

* type string
* value Object

Apply

Type: Function

$3

* context Context
* args Array<Value>

ConfigFunction

Type: Object

$3

* arguments Array<string>
* returns string
* apply Apply

functions

knwon functions

$3

Include definition form a file.

#### Parameters

* file string file name to be included

Returns string content of the file

$3

Replace string.

#### Parameters

* source string input value

Returns string replaced content

$3

Convert string into upper case.

#### Parameters

* source string input value

Returns string uppercase result

$3

Convert string into lower case.

#### Parameters

* source string input value

Returns string lowercase result

$3

Split source string on pattern boundaries.

#### Parameters

* source string
* pattern string

Returns Array<string> separated source

$3

Encrypt a plaintext value.

#### Parameters

* key string
* plaintext string input value

Returns string encrypted value

$3

Decrypt a former encrypted string.

#### Parameters

* key string
* encrypted string

Returns string plaintext

$3

Call executable.

#### Parameters

* executable string path
* arguments Array<string>
* options Object?

Returns string stdout

merge

merge from b into a
When a and b are arrays of values only the none duplaces are appendend to a

$3

* a any
* b any

Returns any merged b into a

install

With npm do:

`shell
npm install config-expander
``

license

BSD-2-Clause