typia/src/transformers/features/misc/MiscLiteralsTransformer.ts

Superfast runtime validators with only one line

import ts from "typescript";

import { MiscLiteralsProgrammer } from "../../../programmers/misc/MiscLiteralsProgrammer";

import { IProject } from "../../IProject";
import { TransformerError } from "../../TransformerError";

export namespace MiscLiteralsTransformer {
  export const transform =
    (project: IProject) =>
    (expression: ts.CallExpression): ts.Expression => {
      // CHECK GENERIC ARGUMENT EXISTENCE
      if (!expression.typeArguments?.[0])
        throw new TransformerError({
          code: "typia.misc.literals",
          message: "generic argument is not specified.",
        });

      // GET TYPE INFO
      const node: ts.TypeNode = expression.typeArguments[0];
      const type: ts.Type = project.checker.getTypeFromTypeNode(node);

      if (type.isTypeParameter())
        throw new TransformerError({
          code: "typia.misc.literals",
          message: "non-specified generic argument.",
        });

      // DO TRANSFORM
      return MiscLiteralsProgrammer.write(project)(type);
    };
}