typia/src/programmers/protobuf/ProtobufEncodeProgrammer.ts

Superfast runtime validators with only one line

import ts from "typescript";

import { ExpressionFactory } from "../../factories/ExpressionFactory";
import { IdentifierFactory } from "../../factories/IdentifierFactory";
import { MetadataCollection } from "../../factories/MetadataCollection";
import { NumericRangeFactory } from "../../factories/NumericRangeFactory";
import { ProtobufFactory } from "../../factories/ProtobufFactory";
import { StatementFactory } from "../../factories/StatementFactory";
import { TypeFactory } from "../../factories/TypeFactory";

import { Metadata } from "../../schemas/metadata/Metadata";
import { MetadataMap } from "../../schemas/metadata/MetadataMap";
import { MetadataObjectType } from "../../schemas/metadata/MetadataObjectType";
import { IProtobufProperty } from "../../schemas/protobuf/IProtobufProperty";
import { IProtobufPropertyType } from "../../schemas/protobuf/IProtobufPropertyType";
import { IProtobufSchema } from "../../schemas/protobuf/IProtobufSchema";

import { IProgrammerProps } from "../../transformers/IProgrammerProps";
import { ITypiaContext } from "../../transformers/ITypiaContext";

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

import { FeatureProgrammer } from "../FeatureProgrammer";
import { IsProgrammer } from "../IsProgrammer";
import { FunctionProgrammer } from "../helpers/FunctionProgrammer";
import { ProtobufUtil } from "../helpers/ProtobufUtil";
import { ProtobufWire } from "../helpers/ProtobufWire";
import { UnionPredicator } from "../helpers/UnionPredicator";
import { decode_union_object } from "../internal/decode_union_object";

export namespace ProtobufEncodeProgrammer {
  export const decompose = (props: {
    context: ITypiaContext;
    modulo: ts.LeftHandSideExpression;
    functor: FunctionProgrammer;
    type: ts.Type;
    name: string | undefined;
  }): FeatureProgrammer.IDecomposed => {
    const collection: MetadataCollection = new MetadataCollection();
    const metadata: Metadata = ProtobufFactory.metadata({
      method: props.modulo.getText(),
      checker: props.context.checker,
      transformer: props.context.transformer,
      collection,
      type: props.type,
    });

    const callEncoder = (writer: string, factory: ts.NewExpression) =>
      StatementFactory.constant({
        name: writer,
        value: ts.factory.createCallExpression(
          ts.factory.createIdentifier("encoder"),
          undefined,
          [factory, ts.factory.createIdentifier("input")],
        ),
      });
    return {
      functions: {
        encoder: StatementFactory.constant({
          name: props.functor.useLocal("encoder"),
          value: write_encoder({
            context: props.context,
            functor: props.functor,
            collection,
            metadata,
          }),
        }),
      },
      statements: [],
      arrow: ts.factory.createArrowFunction(
        undefined,
        undefined,
        [
          IdentifierFactory.parameter(
            "input",
            ts.factory.createTypeReferenceNode(
              props.name ??
                TypeFactory.getFullName({
                  checker: props.context.checker,
                  type: props.type,
                }),
            ),
          ),
        ],
        ts.factory.createTypeReferenceNode("Uint8Array"),
        undefined,
        ts.factory.createBlock(
          [
            callEncoder(
              "sizer",
              ts.factory.createNewExpression(
                props.context.importer.internal("ProtobufSizer"),
                undefined,
                [],
              ),
            ),
            callEncoder(
              "writer",
              ts.factory.createNewExpression(
                props.context.importer.internal("ProtobufWriter"),
                undefined,
                [ts.factory.createIdentifier("sizer")],
              ),
            ),
            ts.factory.createReturnStatement(callWriter("buffer")),
          ],
          true,
        ),
      ),
    };
  };

  export const write = (props: IProgrammerProps): ts.CallExpression => {
    const functor: FunctionProgrammer = new FunctionProgrammer(
      props.modulo.getText(),
    );
    const result: FeatureProgrammer.IDecomposed = decompose({
      ...props,
      functor,
    });
    return FeatureProgrammer.writeDecomposed({
      modulo: props.modulo,
      functor,
      result,
    });
  };

  const write_encoder = (props: {
    context: ITypiaContext;
    functor: FunctionProgrammer;
    collection: MetadataCollection;
    metadata: Metadata;
  }): ts.ArrowFunction => {
    const functors = props.collection
      .objects()
      .filter((obj) => ProtobufUtil.isStaticObject(obj))
      .map((object) =>
        StatementFactory.constant({
          name: `${PREFIX}o${object.index}`,
          value: write_object_function({
            context: props.context,
            functor: props.functor,
            input: ts.factory.createIdentifier("input"),
            object,
            explore: {
              source: "function",
              from: "object",
              tracable: false,
              postfix: "",
            },
          }),
        }),
      );
    return ts.factory.createArrowFunction(
      undefined,
      [
        ts.factory.createTypeParameterDeclaration(
          undefined,
          "Writer",
          props.context.importer.type({
            file: "typia/lib/internal/_IProtobufWriter.js",
            name: "_IProtobufWriter",
          }),
        ),
      ],
      [
        IdentifierFactory.parameter(
          "writer",
          ts.factory.createTypeReferenceNode("Writer"),
        ),
        IdentifierFactory.parameter("input"),
      ],
      ts.factory.createTypeReferenceNode("Writer"),
      undefined,
      ts.factory.createBlock(
        [
          ...props.functor.declareUnions(),
          ...functors,
          ...IsProgrammer.write_function_statements(props),
          ts.factory.createExpressionStatement(
            ts.factory.createCallExpression(
              ts.factory.createIdentifier(
                props.functor.useLocal(
                  `${PREFIX}o${props.metadata.objects[0]?.type.index ?? 0}`,
                ),
              ),
              [],
              [ts.factory.createIdentifier("input")],
            ),
          ),
          ts.factory.createReturnStatement(
            ts.factory.createIdentifier("writer"),
          ),
        ],
        true,
      ),
    );
  };

  const write_object_function = (props: {
    context: ITypiaContext;
    functor: FunctionProgrammer;
    input: ts.Expression;
    object: MetadataObjectType;
    explore: FeatureProgrammer.IExplore;
  }): ts.ArrowFunction => {
    const body: ts.Statement[] = props.object.properties
      .map((p) => {
        const block = decode_property({
          context: props.context,
          functor: props.functor,
          explore: props.explore,
          metadata: p.value,
          protobuf: p.of_protobuf_!,
          input: IdentifierFactory.access(props.input, p.key.getSoleLiteral()!),
        });
        return [
          ts.factory.createExpressionStatement(
            ts.factory.createIdentifier(
              `// property ${JSON.stringify(p.key.getSoleLiteral())}: ${p.value.getName()}`,
            ),
          ),
          ...block.statements,
        ];
      })
      .flat();
    return ts.factory.createArrowFunction(
      undefined,
      undefined,
      [IdentifierFactory.parameter("input")],
      TypeFactory.keyword("any"),
      undefined,
      ts.factory.createBlock(body, true),
    );
  };

  /* -----------------------------------------------------------
    DECODER STATION
  ----------------------------------------------------------- */
  const decode_property = (props: {
    context: ITypiaContext;
    functor: FunctionProgrammer;
    metadata: Metadata;
    protobuf: IProtobufProperty;
    input: ts.Expression;
    explore: FeatureProgrammer.IExplore;
  }): ts.Block => {
    const union: IUnion[] = [];
    for (const schema of props.protobuf.union) {
      //----
      // ATOMICS
      //----
      if (schema.type === "bool")
        union.push({
          is: () =>
            ts.factory.createStrictEquality(
              ts.factory.createStringLiteral("boolean"),
              ts.factory.createTypeOfExpression(props.input),
            ),
          value: () =>
            decode_bool({
              input: props.input,
              index: schema.index,
            }),
        });
      else if (schema.type === "bigint")
        union.push(
          decode_bigint({
            input: props.input,
            type: schema.name,
            candidates: props.protobuf.union
              .filter((s) => s.type === "bigint")
              .map((s) => s.name),
            index: schema.index,
          }),
        );
      else if (schema.type === "number")
        union.push(
          decode_number({
            input: props.input,
            type: schema.name,
            candidates: props.protobuf.union
              .filter((s) => s.type === "number")
              .map((s) => s.name),
            index: schema.index,
          }),
        );
      else if (schema.type === "string")
        union.push({
          is: () =>
            ts.factory.createStrictEquality(
              ts.factory.createStringLiteral("string"),
              ts.factory.createTypeOfExpression(props.input),
            ),
          value: () =>
            decode_bytes({
              method: "string",
              index: schema.index,
              input: props.input,
            }),
        });
      //----
      // INSTANCES
      //----
      else if (schema.type === "bytes")
        union.push({
          is: () => ExpressionFactory.isInstanceOf("Uint8Array", props.input),
          value: () =>
            decode_bytes({
              method: "bytes",
              index: schema.index,
              input: props.input,
            }),
        });
      else if (schema.type === "array")
        union.push({
          is: () => ExpressionFactory.isArray(props.input),
          value: () =>
            decode_array({
              context: props.context,
              functor: props.functor,
              input: props.input,
              schema,
            }),
        });
      else if (schema.type === "map" && schema.map instanceof MetadataMap) {
        union.push({
          is: () => ExpressionFactory.isInstanceOf("Map", props.input),
          value: () =>
            decode_map({
              context: props.context,
              functor: props.functor,
              schema,
              input: props.input,
            }),
        });
      }
      const objectSchemas: Array<
        IProtobufPropertyType.IObject | IProtobufPropertyType.IMap
      > = props.protobuf.union
        .filter((schema) => schema.type === "object" || schema.type === "map")
        .filter(
          (schema) =>
            schema.type === "object" ||
            (schema.type === "map" && schema.map instanceof MetadataObjectType),
        );
      if (objectSchemas.length !== 0)
        union.push({
          is: () =>
            ExpressionFactory.isObject({
              checkNull: true,
              checkArray: false,
              input: props.input,
            }),
          value: () =>
            explore_objects({
              context: props.context,
              functor: props.functor,
              level: 0,
              schemas: objectSchemas,
              explore: {
                ...props.explore,
                from: "object",
              },
              input: props.input,
            }),
        });
    }

    // RETURNS
    const wrapper: (block: ts.Block) => ts.Block =
      props.metadata.isRequired() && props.metadata.nullable === false
        ? (block) => block
        : props.metadata.isRequired() === false &&
            props.metadata.nullable === true
          ? (block) =>
              ts.factory.createBlock(
                [
                  ts.factory.createIfStatement(
                    ts.factory.createLogicalAnd(
                      ts.factory.createStrictInequality(
                        ts.factory.createIdentifier("undefined"),
                        props.input,
                      ),
                      ts.factory.createStrictInequality(
                        ts.factory.createNull(),
                        props.input,
                      ),
                    ),
                    block,
                  ),
                ],
                true,
              )
          : props.metadata.isRequired() === false
            ? (block) =>
                ts.factory.createBlock(
                  [
                    ts.factory.createIfStatement(
                      ts.factory.createStrictInequality(
                        ts.factory.createIdentifier("undefined"),
                        props.input,
                      ),
                      block,
                    ),
                  ],
                  true,
                )
            : (block) =>
                ts.factory.createBlock(
                  [
                    ts.factory.createIfStatement(
                      ts.factory.createStrictInequality(
                        ts.factory.createNull(),
                        props.input,
                      ),
                      block,
                    ),
                  ],
                  true,
                );
    if (union.length === 1) return wrapper(union[0]!.value());
    return wrapper(
      ts.factory.createBlock(
        [
          union
            .map((u, i) =>
              ts.factory.createIfStatement(
                u.is(),
                u.value(),
                i === union.length - 1
                  ? create_throw_error({
                      context: props.context,
                      functor: props.functor,
                      input: props.input,
                      expected: props.metadata.getName(),
                    })
                  : undefined,
              ),
            )
            .reverse()
            .reduce((a, b) =>
              ts.factory.createIfStatement(b.expression, b.thenStatement, a),
            ),
        ],
        true,
      ),
    );
  };

  /* -----------------------------------------------------------
    ATOMIC DECODERS
  ----------------------------------------------------------- */
  const decode_bool = (props: {
    input: ts.Expression;
    index: number | null;
  }): ts.Block =>
    ts.factory.createBlock(
      [
        ...(props.index !== null
          ? [
              decode_tag({
                wire: ProtobufWire.VARIANT,
                index: props.index,
              }),
            ]
          : []),
        callWriter("bool", [props.input]),
      ].map((exp) => ts.factory.createExpressionStatement(exp)),
      true,
    );

  const decode_bigint = (props: {
    candidates: ProtobufAtomic.BigNumeric[];
    type: ProtobufAtomic.BigNumeric;
    input: ts.Expression;
    index: number | null;
  }): IUnion => ({
    is: () =>
      props.candidates.length === 1
        ? ts.factory.createStrictEquality(
            ts.factory.createStringLiteral("bigint"),
            ts.factory.createTypeOfExpression(props.input),
          )
        : ts.factory.createLogicalAnd(
            ts.factory.createStrictEquality(
              ts.factory.createStringLiteral("bigint"),
              ts.factory.createTypeOfExpression(props.input),
            ),
            NumericRangeFactory.bigint(props.type, props.input),
          ),
    value: () =>
      ts.factory.createBlock(
        [
          ...(props.index !== null
            ? [
                decode_tag({
                  wire: ProtobufWire.VARIANT,
                  index: props.index,
                }),
              ]
            : []),
          callWriter(props.type, [props.input]),
        ].map((exp) => ts.factory.createExpressionStatement(exp)),
        true,
      ),
  });

  const decode_number = (props: {
    candidates: ProtobufAtomic.Numeric[];
    type: ProtobufAtomic.Numeric;
    input: ts.Expression;
    index: number | null;
  }): IUnion => ({
    is: () =>
      props.candidates.length === 1
        ? ts.factory.createStrictEquality(
            ts.factory.createStringLiteral("number"),
            ts.factory.createTypeOfExpression(props.input),
          )
        : ts.factory.createLogicalAnd(
            ts.factory.createStrictEquality(
              ts.factory.createStringLiteral("number"),
              ts.factory.createTypeOfExpression(props.input),
            ),
            NumericRangeFactory.number(props.type, props.input),
          ),
    value: () =>
      ts.factory.createBlock(
        [
          ...(props.index !== null
            ? [
                decode_tag({
                  wire: get_numeric_wire(props.type),
                  index: props.index,
                }),
              ]
            : []),
          callWriter(props.type, [props.input]),
        ].map((exp) => ts.factory.createExpressionStatement(exp)),
        true,
      ),
  });

  const decode_container_value = (props: {
    context: ITypiaContext;
    functor: FunctionProgrammer;
    schema: IProtobufPropertyType.IArray["value"];
    index: number;
    kind: "array" | "map";
    input: ts.Expression;
  }): ts.Block => {
    if (props.schema.type === "bool")
      return decode_bool({
        input: props.input,
        index: props.kind === "array" ? null : props.index,
      });
    else if (props.schema.type === "bigint")
      return decode_bigint({
        input: props.input,
        type: props.schema.name,
        candidates: [props.schema.name],
        index: props.kind === "array" ? null : props.index,
      }).value();
    else if (props.schema.type === "number")
      return decode_number({
        input: props.input,
        type: props.schema.name,
        candidates: [props.schema.name],
        index: props.kind === "array" ? null : props.index,
      }).value();
    else if (props.schema.type === "string" || props.schema.type === "bytes")
      return decode_bytes({
        method: props.schema.type,
        input: props.input,
        index: props.index,
      });
    return decode_object({
      context: props.context,
      functor: props.functor,
      schema: props.schema,
      input: props.input,
      index: props.index,
    });
  };

  /* -----------------------------------------------------------
    INSTANCE DECODERS
  ----------------------------------------------------------- */
  const decode_bytes = (props: {
    method: "bytes" | "string";
    index: number;
    input: ts.Expression;
  }): ts.Block =>
    ts.factory.createBlock(
      [
        decode_tag({
          wire: ProtobufWire.LEN,
          index: props.index,
        }),
        callWriter(props.method, [props.input]),
      ].map((expr) => ts.factory.createExpressionStatement(expr)),
      true,
    );

  const decode_array = (props: {
    context: ITypiaContext;
    functor: FunctionProgrammer;
    schema: IProtobufPropertyType.IArray;
    input: ts.Expression;
  }): ts.Block => {
    const value: IProtobufPropertyType.IArray["value"] = props.schema.value;
    const wire: ProtobufWire = (() => {
      if (
        value.type === "object" ||
        value.type === "bytes" ||
        value.type === "string"
      )
        return ProtobufWire.LEN;
      else if (value.type === "number" && value.name === "float")
        return ProtobufWire.I32;
      return ProtobufWire.VARIANT;
    })();
    const forLoop = () =>
      ts.factory.createForOfStatement(
        undefined,
        ts.factory.createVariableDeclarationList(
          [ts.factory.createVariableDeclaration("elem")],
          ts.NodeFlags.Const,
        ),
        props.input,
        decode_container_value({
          kind: "array",
          context: props.context,
          functor: props.functor,
          input: ts.factory.createIdentifier("elem"),
          index: props.schema.index,
          schema: props.schema.value,
        }),
      );
    const length = (block: ts.Block) =>
      ts.factory.createBlock(
        [
          ts.factory.createIfStatement(
            ts.factory.createStrictInequality(
              ExpressionFactory.number(0),
              IdentifierFactory.access(props.input, "length"),
            ),
            block,
          ),
        ],
        true,
      );
    if (wire === ProtobufWire.LEN)
      return length(ts.factory.createBlock([forLoop()], true));
    return length(
      ts.factory.createBlock(
        [
          ts.factory.createExpressionStatement(
            decode_tag({
              wire: ProtobufWire.LEN,
              index: props.schema.index,
            }),
          ),
          ts.factory.createExpressionStatement(callWriter("fork")),
          forLoop(),
          ts.factory.createExpressionStatement(callWriter("ldelim")),
        ],
        true,
      ),
    );
  };

  const decode_object = (props: {
    context: ITypiaContext;
    functor: FunctionProgrammer;
    schema: IProtobufSchema.IObject;
    index: number;
    input: ts.Expression;
  }): ts.Block =>
    ts.factory.createBlock(
      [
        decode_tag({
          wire: ProtobufWire.LEN,
          index: props.index,
        }),
        callWriter("fork"),
        ts.factory.createCallExpression(
          ts.factory.createIdentifier(
            props.functor.useLocal(`${PREFIX}o${props.schema.object.index}`),
          ),
          [],
          [props.input],
        ),
        callWriter("ldelim"),
      ].map(ts.factory.createExpressionStatement),
      true,
    );

  const decode_map = (props: {
    context: ITypiaContext;
    functor: FunctionProgrammer;
    schema: IProtobufPropertyType.IMap;
    input: ts.Expression;
  }): ts.Block => {
    const each: ts.Statement[] = [
      ts.factory.createExpressionStatement(
        decode_tag({
          wire: ProtobufWire.LEN,
          index: props.schema.index,
        }),
      ),
      ts.factory.createExpressionStatement(callWriter("fork")),
      ...decode_container_value({
        kind: "map",
        context: props.context,
        functor: props.functor,
        index: 1,
        input: ts.factory.createIdentifier("key"),
        schema: props.schema.key,
      }).statements,
      ...decode_container_value({
        kind: "map",
        context: props.context,
        functor: props.functor,
        index: 2,
        input: ts.factory.createIdentifier("value"),
        schema: props.schema.value,
      }).statements,
      ts.factory.createExpressionStatement(callWriter("ldelim")),
    ];
    return ts.factory.createBlock(
      [
        ts.factory.createForOfStatement(
          undefined,
          StatementFactory.entry({
            key: "key",
            value: "value",
          }),
          props.input,
          ts.factory.createBlock(each),
        ),
      ],
      true,
    );
  };

  const explore_objects = (props: {
    context: ITypiaContext;
    functor: FunctionProgrammer;
    level: number;
    input: ts.Expression;
    schemas: Array<IProtobufPropertyType.IObject | IProtobufPropertyType.IMap>;
    explore: FeatureProgrammer.IExplore;
  }): ts.Block => {
    const out = (
      schema: IProtobufPropertyType.IObject | IProtobufPropertyType.IMap,
    ) =>
      schema.type === "object"
        ? decode_object({
            context: props.context,
            functor: props.functor,
            schema,
            index: schema.index,
            input: props.input,
          })
        : decode_map({
            context: props.context,
            functor: props.functor,
            schema,
            input: ts.factory.createCallExpression(
              IdentifierFactory.access(
                ts.factory.createIdentifier("Object"),
                "entries",
              ),
              undefined,
              [props.input],
            ),
          });
    if (props.schemas.length === 1) return out(props.schemas[0]!);

    const objects: MetadataObjectType[] = props.schemas.map((s) =>
      s.type === "map" ? (s.map as MetadataObjectType) : s.object,
    );
    const expected: string = `(${objects.map((t) => t.name).join(" | ")})`;
    const indexes: WeakMap<
      MetadataObjectType,
      IProtobufPropertyType.IObject | IProtobufPropertyType.IMap
    > = new WeakMap(objects.map((o, i) => [o, props.schemas[i]!]));
    const specifications: UnionPredicator.ISpecialized[] =
      UnionPredicator.object(objects);

    if (specifications.length === 0) {
      const condition: ts.Expression = decode_union_object({
        checker: (v) =>
          IsProgrammer.decode_object({
            context: props.context,
            functor: props.functor,
            object: v.object,
            input: v.input,
            explore: v.explore,
          }),
        decoder: (v) => ExpressionFactory.selfCall(out(indexes.get(v.object)!)),
        success: (expr) => expr,
        escaper: (v) =>
          create_throw_error({
            context: props.context,
            functor: props.functor,
            expected: v.expected,
            input: v.input,
          }),
        input: props.input,
        explore: props.explore,
        objects,
      });
      return StatementFactory.block(condition);
    }
    const remained: MetadataObjectType[] = objects.filter(
      (o) => specifications.find((s) => s.object === o) === undefined,
    );

    // DO SPECIALIZE
    const condition: ts.IfStatement = specifications
      .filter((spec) => spec.property.key.getSoleLiteral() !== null)
      .map((spec, i, array) => {
        const key: string = spec.property.key.getSoleLiteral()!;
        const accessor: ts.Expression = IdentifierFactory.access(
          props.input,
          key,
        );
        const pred: ts.Expression = spec.neighbor
          ? IsProgrammer.decode({
              context: props.context,
              functor: props.functor,
              input: accessor,
              metadata: spec.property.value,
              explore: {
                ...props.explore,
                tracable: false,
                postfix: IdentifierFactory.postfix(key),
              },
            })
          : ExpressionFactory.isRequired(accessor);
        const schema = indexes.get(spec.object)!;
        return ts.factory.createIfStatement(
          pred,
          ts.factory.createExpressionStatement(
            ExpressionFactory.selfCall(out(schema)),
          ),
          i === array.length - 1
            ? remained.length
              ? ts.factory.createExpressionStatement(
                  ExpressionFactory.selfCall(
                    explore_objects({
                      context: props.context,
                      functor: props.functor,
                      level: props.level + 1,
                      input: props.input,
                      schemas: remained.map((r) => indexes.get(r)!),
                      explore: props.explore,
                    }),
                  ),
                )
              : create_throw_error({
                  context: props.context,
                  functor: props.functor,
                  input: props.input,
                  expected,
                })
            : undefined,
        );
      })
      .reverse()
      .reduce((a, b) =>
        ts.factory.createIfStatement(b.expression, b.thenStatement, a),
      );

    // RETURNS WITH CONDITIONS
    return ts.factory.createBlock([condition], true);
  };

  /* -----------------------------------------------------------
    BACKGROUND FUNCTIONS
  ----------------------------------------------------------- */
  const PREFIX = "_pe";

  const decode_tag = (props: {
    wire: ProtobufWire;
    index: number;
  }): ts.CallExpression =>
    callWriter("uint32", [
      ExpressionFactory.number((props.index << 3) | props.wire),
    ]);

  const get_numeric_wire = (type: ProtobufAtomic.Numeric) =>
    type === "double"
      ? ProtobufWire.I64
      : type === "float"
        ? ProtobufWire.I32
        : ProtobufWire.VARIANT;

  const create_throw_error = (props: {
    context: ITypiaContext;
    functor: FunctionProgrammer;
    expected: string;
    input: ts.Expression;
  }) =>
    ts.factory.createExpressionStatement(
      ts.factory.createCallExpression(
        props.context.importer.internal("throwTypeGuardError"),
        [],
        [
          ts.factory.createObjectLiteralExpression(
            [
              ts.factory.createPropertyAssignment(
                "method",
                ts.factory.createStringLiteral(props.functor.method),
              ),
              ts.factory.createPropertyAssignment(
                "expected",
                ts.factory.createStringLiteral(props.expected),
              ),
              ts.factory.createPropertyAssignment("value", props.input),
            ],
            true,
          ),
        ],
      ),
    );
}

const callWriter = (
  method: string,
  args?: ts.Expression[],
): ts.CallExpression =>
  ts.factory.createCallExpression(
    IdentifierFactory.access(ts.factory.createIdentifier("writer"), method),
    undefined,
    args,
  );

interface IUnion {
  is: () => ts.Expression;
  value: () => ts.Block;
}