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@DanielRosenwasser
Last active May 15, 2017 20:51
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Create and Print a Tree with the TypeScript API
import ts = require("typescript");
function makeFactorialFunction() {
const functionName = ts.createIdentifier("factorial");
const paramName = ts.createIdentifier("n");
const parameter = ts.createParameter(
/*decorators*/ undefined,
/*modifiers*/ undefined,
/*dotDotDotToken*/ undefined,
paramName);
const condition = ts.createBinary(
paramName,
ts.SyntaxKind.LessThanEqualsToken,
ts.createLiteral(1));
const ifBody = ts.createBlock(
[ts.createReturn(ts.createLiteral(1))],
/*multiline*/ true)
const decrementedArg = ts.createBinary(paramName, ts.SyntaxKind.MinusToken, ts.createLiteral(1))
const recurse = ts.createBinary(
paramName,
ts.SyntaxKind.AsteriskToken,
ts.createCall(functionName, /*typeArgs*/undefined, [decrementedArg]));
const statements = [
ts.createIf(condition, ifBody),
ts.createReturn(
recurse
),
];
return ts.createFunctionDeclaration(
/*decorators*/ undefined,
/*modifiers*/[ts.createToken(ts.SyntaxKind.ExportKeyword)],
/*asteriskToken*/ undefined,
functionName,
/*typeParameters*/ undefined,
[parameter],
/*returnType*/ ts.createKeywordTypeNode(ts.SyntaxKind.NumberKeyword),
ts.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);
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