conev

Conev is a module that build environment variables from a source into config. Storing configuration in the environment separate from code is based on The Twelve-Factor App methodology.

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Install

# with npm 
npm install conev
 
# or with Yarn 
yarn add conev

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Usage

Get ConfigBuilder from conev and one or more Sources to use. In this example, the built-in JsonSource is used.

import { ConfigBuilder, JsonSource } from 'conev';

And create Source and set up.

const jsonSource = new JsonSource();

jsonSource    
    .setConfig('basic', basic) // basic is JSON
    .setConfig('dev', dev) // dev is JSON
    .setConfig('prd', prd); // prd is JSON

Create ConfigBuilder and set Environment, add source. (highest priority is added first).

const builder = new ConfigBuilder();

builder
    .setEnv('dev', 'basic')
    .addSource(jsonSource);

Build configuration

const config = await builder.build().refresh(); // This is the result of combining dev and basic.

Use configuration

config.get() // The whole configuration created comes out
config.get('a.b.c'); // Is same as config.get().a.b.c

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Config Builder

class ConfigBuilder {
    setEnv(...env: string[]): ConfigBuilder;
    addEnv(...env: string[]): ConfigBuilder;
    addSource(source: Source, priority?: number): ConfigBuilder;

    build(): Config;
}

ConfigBuilder takes a configuration from the source and creates a new configuration according to the environment. Env and Source have priority. If priority is not defined, highest priority is added first.

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Config

class Config {
    constructor(sources: Source[], env: string[]);
    
    setEnv(...env: string[]): Config;
    addEnv(...env: string[]): Config;
    addSource(source: Source, priority?: number): Config;
    
    refresh(): Promise<Config>;
    validate(): void;
    
    get(key?: string): object;
    set(key: string, value: any): void;
}

config is a container for configuration. config is provided by creating a new configuration from the configuration and environment obtained from source.

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Source

interface Source {
    export(): Promise<Map<string, object>>;
}

Source defines the source from which to get the configuration. Map is returned as the result value of export. The key of this map is environment and the value is the configuration when environment.

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Json Source

class JsonSource {
    constructor(map?: Map<string, object>);
    setConfig(env: string, ...values: object[]): JsonSource
    addConfig(env: string, ...values: object[]): JsonSource;
    removeConfig(env: string): JsonSource;
    export(): Promise<Map<string, object>>;
}

JsonSource defines the source from JSON. Use setConfig to add a configuration for a new environment or removeConfig to delete a configuration. Map is returned as the result value of export. The key of this map is environment and the value is the configuration when environment.

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Json File Source

class JsonFileSource {
    constructor(fileMap?: Map<string, string>);
    setConfig(env: string, ...filenames: string[]): JsonFileSource;
    addConfig(env: string, ...filename: string[]): JsonFileSource;
    removeConfig(env: string): JsonFileSource;
    export(): Promise<Map<string, object>>;
}

JsonFileSource defines the source from JSON file. Use setConfig to add a configuration for a new environment or removeConfig to delete a configuration. Map is returned as the result value of export. The key of this map is environment and the value is the configuration when environment.

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Expansion

It can be extended by defining a new Source.