Saturday, 30 May, 2020 UTC


This lesson will demonstrate how to recreate a simplified version of the popular [lodash.merge]( method from scratch. First we'll create a test file with two objects that we want to merge together and demonstrate the output after running them through lodash.merge , then we'll go about creating our own version of the function. Our initial version will support only one `source` object to merge in, and will support only the subset of JavaScript syntax supported by the JSON spec, including the following types: - `boolean`, `number`, `string` - object literal - array After getting basic types to merge we'll show off two methods for merging arrays, either using [concat]( or recursively going through the children and merging them. Finally we'll build our own `isObject` function to check for object literals and recursively apply our `mergeJSON` function to any object literals in our `source` object. And last we'll add support for multiple `source` objects to be merged in using a `for...of` loop. **Note** The `mergeJSON` method we create approximates the `lodash.merge` functionality but does not seek to replace it. It may be useful for some use cases, but primarily it's meant to be a tool for understanding how to merge objects with recursion.