Sort the bug before you fix the bug

Drop each symptom into the first diagnostic bucket you should use. Syntax or parse Reference or scope Runtime value shape Logic rule Async order SyntaxError: missing ) after argument list Unexpected token else after editing braces ReferenceError: subtotal is not defined A helper works in one module but is not imported in another Cannot read properties of undefined (reading 'name') items.map is not a function VIP discount applies to trial users with no console error A promise log appears before a zero-delay timer log

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