generate cli help from types

cli-help.ts

/**
 *
 * help({fileName: "", typeName: ""})
 *
 */
import * as ts from "typescript";

interface HelpParameter {
  fileName: string;
  typeName: string;
}

interface CliOption {
  name: string;
  typeString: string;
}

export function doc() {

}
export function help(param: HelpParameter) {

  const options = {};
  const program = ts.createProgram([param.fileName], options);
  const source = program.getSourceFile(param.fileName);
  const checker = program.getTypeChecker();

  const cliOptions = getCliOptions();
  const summary = cliOptions.map((opt: CliOption) => {
    return `[--${opt.name}]`;
  }).join("")

  console.log("usage: ");
  console.log(`  $ cli-help ${summary}`);
  console.log("");

  console.log("options: ");

  cliOptions.forEach((opt: CliOption) => {
    console.log(`  ${opt.name}: ${opt.typeString}`);
  })

  function getCliOptions() {
    const symbols: CliOption[] = [];

    ts.forEachChild(source, function next(node) {
      if (
        (ts.isInterfaceDeclaration(node) || ts.isTypeAliasDeclaration(node)) &&
        node.name
      ) {
        const type = checker.getTypeAtLocation(node);

        const ctorSymbol = checker.getSymbolAtLocation(node.name);
        if (!ctorSymbol) return;

        if (ctorSymbol.name === param.typeName) {
          type.getProperties().map((symbol: ts.Symbol) => {
            const type = checker.getTypeOfSymbolAtLocation(symbol, symbol.valueDeclaration!);
            // ts.TypeFormatFlags.AddUndefined が効かない？
            symbols.push({
              name: symbol.name,
              typeString: checker.typeToString(type, undefined, ts.TypeFormatFlags.AddUndefined)
            });
          });
        }
      }
    });

    return symbols;
  }

}