Function merge

merge<K, V>(map: Map<K, V>): ((key: K, value: V, remappingFunction: ((oldValue: undefined | V, value: V) => undefined | V)) => undefined | V)
Mutation

Remark
only returns undefined if mappingFunction returns undefined

Example
Set a Map entry if the key is absent
```
const map = new Map([[1, 2]]);
merge(map)(1, 3, (old, value) => old + value);
console.log(map); // Map([[1, 5]])
```
Type Parameters
- K
  
  the Map key type
- V
  
  the Map value type
Parameters
- map: Map<K, V>
  
  the Map to set the entry
Returns ((key: K, value: V, remappingFunction: ((oldValue: undefined | V, value: V) => undefined | V)) => undefined | V)
- - (key: K, value: V, remappingFunction: ((oldValue: undefined | V, value: V) => undefined | V)): undefined | V
  - Parameters
    - key: K
    - value: V
    - remappingFunction: ((oldValue: undefined | V, value: V) => undefined | V)
      
      (oldValue: undefined | V, value: V): undefined | V
      
      Parameters
      
      oldValue: undefined | V
      
      value: V
      
      Returns undefined | V
    Returns undefined | V
- Defined in packages/map/src/merge.ts:22

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