https://github.com/arlac77/expression-expander

expands ${to be evaluated} expressions in object graphs
https://github.com/arlac77/expression-expander

Last synced: about 1 year ago
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expands ${to be evaluated} expressions in object graphs

• Host: GitHub
• URL: https://github.com/arlac77/expression-expander
• Owner: arlac77
• License: 0bsd
• Created: 2015-08-22T11:13:28.000Z (almost 11 years ago)
• Default Branch: master
• Last Pushed: 2025-04-06T00:06:24.000Z (about 1 year ago)
• Last Synced: 2025-04-06T00:24:16.056Z (about 1 year ago)
• Language: JavaScript
• Homepage:
• Size: 2.54 MB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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## Expression Expander

Expands *\\${to be evaluated}* expressions in object graphs. The actual expression syntax inside of the *\\${evaluated}* is not defined within this module (only simple key lookup)

# example

## file.js

```js

import { createContext } from "expression-expander";

const context = createContext();

context.properties = { aKey: "aValue", moreKeys: { a: 1, b: 2 } };

// expanding whole expressions at the key position

console.log(

  JSON.stringify(

    context.expand({ simple: "${aKey}", complex: { "${moreKeys}": {} } })

  )

);

```

Output

```json

{ "simple": "aValue", "complex": { "a": 1, "b": 2 } }

```

## Any Object of the following types may be expanded

*   String

*   Number

*   BigInt

*   Buffer

*   Object (key and value will be expanded)

*   Array

*   Map (key and value will be expanded)

*   Set

*   Boolean

*   Promise

# API

### Table of Contents

*   [Evaluator](#evaluator)

    *   [Parameters](#parameters)

*   [PathEntry](#pathentry)

    *   [Properties](#properties)

*   [Quoter](#quoter)

    *   [Parameters](#parameters-1)

*   [Expander](#expander)

    *   [Parameters](#parameters-2)

*   [ExpressionExpander](#expressionexpander)

    *   [Properties](#properties-1)

*   [createContext](#createcontext)

    *   [Parameters](#parameters-3)

*   [expand](#expand)

    *   [Parameters](#parameters-4)

*   [properties](#properties-2)

## Evaluator

Type: [Function](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function)

### Parameters

*   `expression` **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** 

*   `context` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** 

*   `path` **\[[PathEntry](#pathentry)]** 

Returns **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** expression evaluation result

## PathEntry

Type: [Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)

### Properties

*   `value` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** 

## Quoter

Type: [Function](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function)

### Parameters

*   `value` **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** to be quoted

Returns **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)** quoted value

## Expander

Type: [Function](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Statements/function)

### Parameters

*   `value` **([string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String) | [boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean) | [number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number) | bigint | [Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object) | [Map](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Map) | [Set](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Set))** 

*   `path` **[Array](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array)<[PathEntry](#pathentry)>?** 

Returns **([string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String) | [boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean) | [number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number) | bigint | [Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object) | [Map](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Map) | [Set](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Set))** expression evaluation result

## ExpressionExpander

Type: [Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)

### Properties

*   `properties` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)** 

*   `expand` **[Expander](#expander)** 

## createContext

Creates a new expansion context

### Parameters

*   `options` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** object with the following keys

    *   `options.leftMarker` **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)?** lead in of expression

    *   `options.rightMarker` **[string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String)?** lead out of expression

    *   `options.markerRegexp` **([RegExp](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/RegExp) | [string](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/String))?** expression with lead in / out

    *   `options.valueQuoter` **[Quoter](#quoter)?** to quote expanded values

        by default no special quoting is done and the evaluated result will be direcly

        inserted into the output string

    *   `options.evaluate` **[Evaluator](#evaluator)?** evaluate(expression,context,path) function to evaluate expressions

        the default evaluation function does a lookup into the properties

    *   `options.keepUndefinedValues` **[boolean](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean)?** true: is expression resolves to undefind the original string will be used (with surrounding ${})

    *   `options.maxNestingLevel` **[number](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number)?** max number of recursive calls to expand defaults to 20

    *   `options.properties` **[Object](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object)?** default properties to evaluate expression against

Returns **[ExpressionExpander](#expressionexpander)** newly created expansion context

## expand

Type: [Expander](#expander)

### Parameters

*   `object`  

*   `path`   (optional, default `[{value:object}]`)

## properties

Properties used for the default expander implementation

# install

With [npm](http://npmjs.org) do:

```shell

npm install expression-expander

```

# license

BSD-2-Clause