Documentation: "Creating and Printing a TypeScript AST" example does not work after v4.9.5

[murtyjones]

🔎 Search Terms

"Creating and Printing a TypeScript AST"

🕗 Version & Regression Information

This example from the docs no loner works after v4.9.5

⏯ Playground Link

No response

💻 Code

The code from this section of the docs:

import ts = require("typescript");

function makeFactorialFunction() {
  const functionName = ts.factory.createIdentifier("factorial");
  const paramName = ts.factory.createIdentifier("n");
  const parameter = ts.factory.createParameterDeclaration(
    /*decorators*/ undefined,
    /*modifiers*/ undefined,
    /*dotDotDotToken*/ undefined,
    paramName
  );

  const condition = ts.factory.createBinaryExpression(paramName, ts.SyntaxKind.LessThanEqualsToken, ts.factory.createNumericLiteral(1));
  const ifBody = ts.factory.createBlock([ts.factory.createReturnStatement(ts.factory.createNumericLiteral(1))], /*multiline*/ true);

  const decrementedArg = ts.factory.createBinaryExpression(paramName, ts.SyntaxKind.MinusToken, ts.factory.createNumericLiteral(1));
  const recurse = ts.factory.createBinaryExpression(paramName, ts.SyntaxKind.AsteriskToken, ts.factory.createCallExpression(functionName, /*typeArgs*/ undefined, [decrementedArg]));
  const statements = [ts.factory.createIfStatement(condition, ifBody), ts.factory.createReturnStatement(recurse)];

  return ts.factory.createFunctionDeclaration(
    /*decorators*/ undefined,
    /*modifiers*/ [ts.factory.createToken(ts.SyntaxKind.ExportKeyword)],
    /*asteriskToken*/ undefined,
    functionName,
    /*typeParameters*/ undefined,
    [parameter],
    /*returnType*/ ts.factory.createKeywordTypeNode(ts.SyntaxKind.NumberKeyword),
    ts.factory.createBlock(statements, /*multiline*/ true)
  );
}

const resultFile = ts.createSourceFile("someFileName.ts", "", ts.ScriptTarget.Latest, /*setParentNodes*/ false, ts.ScriptKind.TS);
const printer = ts.createPrinter({ newLine: ts.NewLineKind.LineFeed });

const result = printer.printNode(ts.EmitHint.Unspecified, makeFactorialFunction(), resultFile);
console.log(result);

🙁 Actual behavior

/path/to/playground/node_modules/typescript/lib/typescript.js:110025
      Debug.fail(`Unhandled SyntaxKind: ${Debug.formatSyntaxKind(node.kind)}.`);
            ^

Error: Debug Failure. Unhandled SyntaxKind: Unknown.
    at pipelineEmitWithHintWorker (/path/to/playground/node_modules/typescript/lib/typescript.js:110025:13)
    at pipelineEmitWithHint (/path/to/playground/node_modules/typescript/lib/typescript.js:109566:9)
    at pipelineEmitWithComments (/path/to/playground/node_modules/typescript/lib/typescript.js:113345:7)
    at pipelineEmit (/path/to/playground/node_modules/typescript/lib/typescript.js:109515:7)
    at emit (/path/to/playground/node_modules/typescript/lib/typescript.js:109483:7)
    at emitFunctionDeclarationOrExpression (/path/to/playground/node_modules/typescript/lib/typescript.js:111284:7)
    at emitFunctionDeclaration (/path/to/playground/node_modules/typescript/lib/typescript.js:111274:7)
    at pipelineEmitWithHintWorker (/path/to/playground/node_modules/typescript/lib/typescript.js:109746:20)
    at pipelineEmitWithHint (/path/to/playground/node_modules/typescript/lib/typescript.js:109566:9)
    at pipelineEmitWithComments (/path/to/playground/node_modules/typescript/lib/typescript.js:113345:7)

Node.js v18.18.0

🙂 Expected behavior

i assume that the compiler error is correct due to some kind of breaking change going from 4.9.5 to 5.0.0. so probably the example needs to be updated so that the program successfully runs and produces:

export function factorial(n): number {
    if (n <= 1) {
        return 1;
    }
    return n * factorial(n - 1);
}

Additional information about the issue

Note also that there are some deprecated APIs in the example:

DeprecationWarning: 'createParameterDeclaration' has been deprecated since v4.8.0. Decorators have been combined with modifiers. Callers should switch to an overload that does not accept a 'decorators' parameter.
DeprecationWarning: 'createFunctionDeclaration' has been deprecated since v4.8.0. Decorators are no longer supported for this function. Callers should switch to an overload that does not accept a 'decorators' parameter.