json-mod

JSON modification protocol

Update JSON object with simple operations such as append, modify, remove and fetch. I know fetch is not a sort of modification but I think we should see an object before modification.

Data types

ResourceValue

type SingleValue = string | number;
type KeyValue = { [key: string]: ResourceValue };
type ArrayValue = ResourceValue[];
type ResourceValue = KeyValue | ArrayValue | SingleValue;

path

This is a string value and a expression of JSON path with a . delimiter.

root.some.thing.value.key

Operations

I think test codes can help to use this library.

Append

interface AppendOperation {
  operation: "append";
  resource: ResourceValue | null;
  path: string;
  value: KeyValue | ArrayValue;
  upsert: boolean;
}

Add a new value into the resource with the specified path. If there is no parent for that path, it would create all ancestor nodes as KeyValue. If upsert is true, it would update a new value even if already has an exising value in that path. Otherwise, it would throw an error.

Modify

interface ModifyOperation {
  operation: "modify";
  resource: ResourceValue | null;
  path: string;
  value: KeyValue | ArrayValue;
}

Update a new value into the resource with the specified path. If path is invalid or there is an exising value, it would throw an error.

Remove

type CurrentKey = undefined;
type MultipleSubKeys = string[];

interface RemoveOperation {
  operation: "remove";
  resource: ResourceValue | null;
  path: string;
  key: CurrentKey | MultipleSubKeys;
}

Delete a path from the resource if value is undefined, or delete keys in value from the resource with the specified path. It would be ignored even if there is nothing to delete.

Fetch

type CurrentKey = undefined;
type MultipleSubKeys = string[];

interface FetchOperation {
  operation: "fetch";
  resource: ResourceValue | null;
  path: string;
  key: CurrentKey | MultipleSubKeys;
}

Fetch a value or values from the resource with the specified path. If path is empty, it would fetch a whole thing. If key is defined as array, it would return values which can be null[] when there are no values mapped with keys.

License

MIT