typia/src/transformers/features/json/JsonSchemaTransformer.ts

Superfast runtime validators with only one line

import ts from "typescript";

import { LiteralFactory } from "../../../factories/LiteralFactory";
import { MetadataCollection } from "../../../factories/MetadataCollection";
import { MetadataFactory } from "../../../factories/MetadataFactory";

import { Metadata } from "../../../schemas/metadata/Metadata";

import { JsonSchemaProgrammer } from "../../../programmers/json/JsonSchemaProgrammer";
import { JsonSchemasProgrammer } from "../../../programmers/json/JsonSchemasProgrammer";

import { ValidationPipe } from "../../../typings/ValidationPipe";

import { IJsonSchemaUnit } from "../../../module";
import { ITransformProps } from "../../ITransformProps";
import { TransformerError } from "../../TransformerError";

export namespace JsonSchemaTransformer {
  export const transform = (
    props: Pick<ITransformProps, "context" | "expression">,
  ): ts.Expression => {
    if (!props.expression.typeArguments?.length)
      throw new TransformerError({
        code: "typia.json.schema",
        message: "no generic argument.",
      });

    //----
    // GET ARGUMENTS
    //----
    // VALIDATE TUPLE ARGUMENTS
    const top: ts.Node | undefined = props.expression.typeArguments[0];
    if (top === undefined || ts.isTypeNode(top) === false)
      return props.expression;

    // GET TYPES
    const type: ts.Type = props.context.checker.getTypeFromTypeNode(top);
    if (type.isTypeParameter())
      throw new TransformerError({
        code: "typia.json.schema",
        message: "non-specified generic argument.",
      });

    // ADDITIONAL PARAMETERS
    const version: "3.0" | "3.1" = getParameter<"3.0" | "3.1">({
      checker: props.context.checker,
      name: "Version",
      is: (str) => str === "3.0" || str === "3.1",
      cast: (str) => str as "3.0" | "3.1",
      default: () => "3.1",
    })(props.expression.typeArguments[1]);

    //----
    // GENERATORS
    //----
    // METADATA
    const analyze = (validate: boolean): Metadata => {
      const results: ValidationPipe<Metadata, MetadataFactory.IError> =
        MetadataFactory.analyze({
          checker: props.context.checker,
          transformer: props.context.transformer,
          options: {
            absorb: validate,
            constant: true,
            escape: true,
            validate:
              validate === true ? JsonSchemasProgrammer.validate : undefined,
          },
          collection: new MetadataCollection({
            replace: MetadataCollection.replace,
          }),
          type,
        });
      if (results.success === false)
        throw TransformerError.from({
          code: "typia.json.schema",
          errors: results.errors,
        });
      return results.data;
    };
    analyze(true);

    // APPLICATION
    const app: IJsonSchemaUnit<any> = JsonSchemaProgrammer.write({
      version,
      metadata: analyze(false),
    });
    return ts.factory.createAsExpression(
      LiteralFactory.write(app),
      props.context.importer.type({
        file: "typia",
        name: "IJsonSchemaUnit",
        arguments: [
          ts.factory.createLiteralTypeNode(
            ts.factory.createStringLiteral(version),
          ),
        ],
      }),
    );
  };

  const getParameter =
    <Value>(props: {
      checker: ts.TypeChecker;
      name: string;
      is: (value: string) => boolean;
      cast: (value: string) => Value;
      default: () => Value;
    }) =>
    (node: ts.TypeNode | undefined): Value => {
      if (!node) return props.default();

      // CHECK LITERAL TYPE
      const type: ts.Type = props.checker.getTypeFromTypeNode(node);
      if (
        !type.isLiteral() &&
        (type.getFlags() & ts.TypeFlags.BooleanLiteral) === 0
      )
        throw new TransformerError({
          code: "typia.json.schema",
          message: `generic argument "${props.name}" must be constant.`,
        });

      // GET VALUE AND VALIDATE IT
      const value = type.isLiteral()
        ? type.value
        : props.checker.typeToString(type);
      if (typeof value !== "string" || props.is(value) === false)
        throw new TransformerError({
          code: "typia.json.schema",
          message: `invalid value on generic argument "${props.name}".`,
        });
      return props.cast(value);
    };
}