Write down the input contract and the failure cases before coding.
tests
RUNTIME OUTPUT
Ready to run the file open above against 1 test.
Runs the open file in a restricted browser worker
LEARN FROM THE SOLUTION
Why the solution works.
The reducer treats the grouping object as an accumulator. Copying the current bucket and object keeps the function pure, which is useful when data may be held in UI state or reused elsewhere.
What this exercise teaches
Objects
Array iteration
Accumulation
A PRACTICAL PLAN
Work through Group orders by status with intent.
Translate the contract.Turn the requirements into a short checklist before editing your-solution.js.
Use the example as evidence.Predict the result for the supplied input, then add one boundary case such as an empty value, a limit, or unexpected input.
Review the implementation.Compare your choices against solution.js only after a real attempt.
EXERCISE FAQ
Before you move on.
What does “Group orders by status” teach?
This beginner JavaScript exercise focuses on Objects, Array iteration, Accumulation. Its requirements define the exact behavior to implement before you write code.
How should I validate this JavaScript solution?
Start with the displayed example input and expected output, then test a boundary case suggested by the requirements. Open your-solution.js and select Run code. The browser executes that file in an isolated worker against the visible test cases.
When should I open the reference solution?
Attempt Group orders by status first. Then open the read-only solution file to compare the contract, edge-case handling, and implementation choices—not simply to copy the final code.
