typia/src/transformers/internal/GenericTransformer.ts

Superfast runtime validators with only one line

import ts from "typescript";

import { IProgrammerProps } from "../IProgrammerProps";
import { ITransformProps } from "../ITransformProps";
import { TransformerError } from "../TransformerError";

export namespace GenericTransformer {
  export interface IProps extends ITransformProps {
    method: string;
    write: (props: IProgrammerProps) => ts.Expression | ts.ArrowFunction;
  }

  export const scalar = (props: IProps) => {
    // CHECK PARAMETER
    if (props.expression.arguments.length === 0)
      throw new TransformerError({
        code: `typia.${props.method}`,
        message: `no input value.`,
      });

    // GET TYPE INFO
    const [type, node, generic]: [ts.Type, ts.Node, boolean] =
      props.expression.typeArguments && props.expression.typeArguments[0]
        ? [
            props.context.checker.getTypeFromTypeNode(
              props.expression.typeArguments[0],
            ),
            props.expression.typeArguments[0],
            true,
          ]
        : [
            props.context.checker.getTypeAtLocation(
              props.expression.arguments[0]!,
            ),
            props.expression.arguments[0]!,
            false,
          ];
    if (type.isTypeParameter())
      throw new TransformerError({
        code: `typia.${props.method}`,
        message: `non-specified generic argument.`,
      });

    // DO TRANSFORM
    return ts.factory.createCallExpression(
      props.write({
        context: props.context,
        modulo: props.modulo,
        type,
        name: generic
          ? node.getFullText().trim()
          : getTypeName({
              checker: props.context.checker,
              type,
              node,
            }),
      }),
      undefined,
      props.expression.arguments,
    );
  };

  export const factory = (props: IProps) => {
    // CHECK GENERIC ARGUMENT EXISTENCE
    if (!props.expression.typeArguments?.[0])
      throw new TransformerError({
        code: `typia.${props.method}`,
        message: `generic argument is not specified.`,
      });

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

    if (type.isTypeParameter())
      throw new TransformerError({
        code: `typia.${props.method}`,
        message: `non-specified generic argument.`,
      });

    // DO TRANSFORM
    return props.write({
      context: props.context,
      modulo: props.modulo,
      type,
      name: node.getFullText().trim(),
      init: props.expression.arguments[0],
    });
  };

  const getTypeName = (props: {
    checker: ts.TypeChecker;
    type: ts.Type;
    node: ts.Node;
  }): string =>
    props.checker.typeToString(
      props.type,
      props.node,
      ts.TypeFormatFlags.NodeBuilderFlagsMask,
    );
}