function validateDiscriminator()

in packages/typespec-powershell/src/utils/modelUtils.ts [588:662]

• 72 lines of code
• 12 McCabe index (conditional complexity)

function validateDiscriminator(
  program: Program,
  discriminator: Discriminator,
  derivedModels: readonly Model[]
): boolean {
  const { propertyName } = discriminator;
  const retVals = derivedModels.map((t) => {
    const prop = getProperty(t, propertyName);
    if (!prop) {
      reportDiagnostic(program, {
        code: "discriminator",
        messageId: "missing",
        target: t
      });
      return false;
    }
    let retval = true;
    if (
      !isOasString(prop.type) &&
      prop.type.kind !== "EnumMember" &&
      prop.type.kind !== "Enum"
    ) {
      reportDiagnostic(program, {
        code: "discriminator",
        messageId: "type",
        target: prop
      });
      retval = false;
    }
    if (prop.optional) {
      reportDiagnostic(program, {
        code: "discriminator",
        messageId: "required",
        target: prop
      });
      retval = false;
    }
    return retval;
  });
  // Map of discriminator value to the model in which it is declared
  const discriminatorValues = new Map<string, string>();
  for (const t of derivedModels) {
    // Get the discriminator property directly in the child model
    const prop = t.properties?.get(propertyName);
    // Issue warning diagnostic if discriminator property missing or is not a string literal
    if (!prop || !isStringLiteral(prop.type)) {
      reportDiagnostic(program, {
        code: "discriminator-value",
        messageId: "literal",
        target: prop || t
      });
    }
    if (prop) {
      const vals = getStringValues(prop.type);
      vals.forEach((val) => {
        if (discriminatorValues.has(val)) {
          reportDiagnostic(program, {
            code: "discriminator",
            messageId: "duplicate",
            format: {
              val: val,
              model1: discriminatorValues.get(val)!,
              model2: t.name
            },
            target: prop
          });
          retVals.push(false);
        } else {
          discriminatorValues.set(val, t.name);
        }
      });
    }
  }
  return retVals.every((v) => v);
}