---
lang: en
title: 'API docs: context.resolveuntil'
keywords: LoopBack 4.0, LoopBack 4
sidebar: lb4_sidebar
permalink: /doc/en/lb4/apidocs.context.resolveuntil.html
---

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[Home](./index.md) &gt; [@loopback/context](./context.md) &gt; [resolveUntil](./context.resolveuntil.md)

## resolveUntil() function

Resolve an iterator of source values into a result until the evaluator returns `true`

<b>Signature:</b>

```typescript
export declare function resolveUntil<T, V>(source: Iterator<T>, resolver: (sourceVal: T) => ValueOrPromise<V | undefined>, evaluator: (sourceVal: T, targetVal: V | undefined) => boolean): ValueOrPromise<V | undefined>;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  source | <code>Iterator&lt;T&gt;</code> | The iterator of source values |
|  resolver | <code>(sourceVal: T) =&gt; ValueOrPromise&lt;V &#124; undefined&gt;</code> | The resolve function that maps the source value to a result |
|  evaluator | <code>(sourceVal: T, targetVal: V &#124; undefined) =&gt; boolean</code> | The evaluate function that decides when to stop |

<b>Returns:</b>

`ValueOrPromise<V | undefined>`


