Function buildConditionalSelect

packages/db/src/query/builder/index.ts:1056–1082

(
  wrapper: CaseWhenWrapper,
  parentAliases: Array<string>,
  fieldName?: string,
)

}

function buildConditionalSelect(
  wrapper: CaseWhenWrapper,
  parentAliases: Array<string>,
  fieldName?: string,
): ConditionalSelect {
  const args = wrapper.args
  if (args.length < 2) {
    throw new Error(`caseWhen() requires at least two arguments`)
  }

  const hasDefaultValue = args.length % 2 === 1
  const pairCount = Math.floor(args.length / 2)
  const branches = []

  for (let i = 0; i < pairCount; i++) {
    branches.push({
      condition: toExpression(args[i * 2]),
      value: buildNestedSelect(args[i * 2 + 1], parentAliases, fieldName),
    })
  }

  const defaultValue = hasDefaultValue
    ? buildNestedSelect(args[args.length - 1], parentAliases, fieldName)
    : undefined

  return new ConditionalSelect(branches, defaultValue)
}

/**
 * Recursively collects all PropRef nodes from an expression tree.