Function getInputPreview

lib/internal/repl/utils.js:302–367

(input, callback)

  // This returns a code preview for arbitrary input code.
  function getInputPreview(input, callback) {
    // For similar reasons as `defaultEval`, wrap expressions starting with a
    // curly brace with parenthesis.
    if (!wrapped && input[0] === '{' && input[input.length - 1] !== ';' && isValidSyntax(input)) {
      input = `(${input})`;
      wrapped = true;
    }
    sendInspectorCommand((session) => {
      session.post('Runtime.evaluate', {
        expression: input,
        throwOnSideEffect: true,
        timeout: 333,
        contextId: repl[contextSymbol],
      }, (error, preview) => {
        if (error) {
          callback(error);
          return;
        }
        const { result } = preview;
        if (result.value !== undefined) {
          callback(null, inspect(result.value, previewOptions));
        // Ignore EvalErrors, SyntaxErrors and ReferenceErrors. It is not clear
        // where they came from and if they are recoverable or not. Other errors
        // may be inspected.
        } else if (preview.exceptionDetails &&
                   (result.className === 'EvalError' ||
                    result.className === 'SyntaxError' ||
                    // Report ReferenceError in case the strict mode is active
                    // for input that has no completions.
                    (result.className === 'ReferenceError' &&
                     (hasCompletions || !isInStrictMode(repl))))) {
          callback(null, null);
        } else if (result.objectId) {
          // The writer options might change and have influence on the inspect
          // output. The user might change e.g., `showProxy`, `getters` or
          // `showHidden`. Use `inspect` instead of `JSON.stringify` to keep
          // `Infinity` and similar intact.
          const inspectOptions = inspect({
            ...repl.writer.options,
            colors: false,
            depth: 1,
            compact: true,
            breakLength: Infinity,
          }, previewOptions);
          session.post('Runtime.callFunctionOn', {
            functionDeclaration:
              `(v) =>
                    Reflect
                    .getOwnPropertyDescriptor(globalThis, 'util')
                    .get().inspect(v, ${inspectOptions})`,
            objectId: result.objectId,
            arguments: [result],
          }, (error, preview) => {
            if (error) {
              callback(error);
            } else {
              callback(null, preview.result.value);
            }