Code Smell 155 — Multiple Promises

The page says that waiting for promises in a sorted order can block work unnecessarily. If the rule is to wait for all operations, the code should let them run in parallel and collect the results together.

Reading notes

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• The smell is described as indeterminism and a performance bottleneck.
• The suggested solution is to wait for all promises at once.
• The context compares this to semaphores and the need to wait until all conditions are met, regardless of ordering.
• The wrong example awaits fetchOne before fetchTwo, which prevents parallel execution.
• The right example uses Promise.all with fetchOne and fetchTwo together.
• The smell is marked as semi-automatic and semantic, with linters able to find related promise-waiting patterns.
• The conclusion says software should stay close to real-world business rules and avoid forcing a particular order when the rule only requires all operations to finish.