denoland-deno/core/error.js

// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.

((window) => {
  // Some of the code here is adapted directly from V8 and licensed under a BSD
  // style license available here: https://github.com/v8/v8/blob/24886f2d1c565287d33d71e4109a53bf0b54b75c/LICENSE.v8
  function patchCallSite(callSite, location) {
    return {
      getThis() {
        return callSite.getThis();
      },
      getTypeName() {
        return callSite.getTypeName();
      },
      getFunction() {
        return callSite.getFunction();
      },
      getFunctionName() {
        return callSite.getFunctionName();
      },
      getMethodName() {
        return callSite.getMethodName();
      },
      getFileName() {
        return location.fileName;
      },
      getLineNumber() {
        return location.lineNumber;
      },
      getColumnNumber() {
        return location.columnNumber;
      },
      getEvalOrigin() {
        return callSite.getEvalOrigin();
      },
      isToplevel() {
        return callSite.isToplevel();
      },
      isEval() {
        return callSite.isEval();
      },
      isNative() {
        return callSite.isNative();
      },
      isConstructor() {
        return callSite.isConstructor();
      },
      isAsync() {
        return callSite.isAsync();
      },
      isPromiseAll() {
        return callSite.isPromiseAll();
      },
      getPromiseIndex() {
        return callSite.getPromiseIndex();
      },
    };
  }

  // Keep in sync with `cli/fmt_errors.rs`.
  function formatLocation(callSite) {
    if (callSite.isNative()) {
      return "native";
    }

    let result = "";

    const fileName = callSite.getFileName();

    if (fileName) {
      result += fileName;
    } else {
      if (callSite.isEval()) {
        const evalOrigin = callSite.getEvalOrigin();
        if (evalOrigin == null) {
          throw new Error("assert evalOrigin");
        }
        result += `${evalOrigin}, `;
      }
      result += "<anonymous>";
    }

    const lineNumber = callSite.getLineNumber();
    if (lineNumber != null) {
      result += `:${lineNumber}`;

      const columnNumber = callSite.getColumnNumber();
      if (columnNumber != null) {
        result += `:${columnNumber}`;
      }
    }

    return result;
  }

  // Keep in sync with `cli/fmt_errors.rs`.
  function formatCallSite(callSite) {
    let result = "";
    const functionName = callSite.getFunctionName();

    const isTopLevel = callSite.isToplevel();
    const isAsync = callSite.isAsync();
    const isPromiseAll = callSite.isPromiseAll();
    const isConstructor = callSite.isConstructor();
    const isMethodCall = !(isTopLevel || isConstructor);

    if (isAsync) {
      result += "async ";
    }
    if (isPromiseAll) {
      result += `Promise.all (index ${callSite.getPromiseIndex()})`;
      return result;
    }
    if (isMethodCall) {
      const typeName = callSite.getTypeName();
      const methodName = callSite.getMethodName();

      if (functionName) {
        if (typeName) {
          if (!functionName.startsWith(typeName)) {
            result += `${typeName}.`;
          }
        }
        result += functionName;
        if (methodName) {
          if (!functionName.endsWith(methodName)) {
            result += ` [as ${methodName}]`;
          }
        }
      } else {
        if (typeName) {
          result += `${typeName}.`;
        }
        if (methodName) {
          result += methodName;
        } else {
          result += "<anonymous>";
        }
      }
    } else if (isConstructor) {
      result += "new ";
      if (functionName) {
        result += functionName;
      } else {
        result += "<anonymous>";
      }
    } else if (functionName) {
      result += functionName;
    } else {
      result += formatLocation(callSite);
      return result;
    }

    result += ` (${formatLocation(callSite)})`;
    return result;
  }

  function evaluateCallSite(callSite) {
    return {
      this: callSite.getThis(),
      typeName: callSite.getTypeName(),
      function: callSite.getFunction(),
      functionName: callSite.getFunctionName(),
      methodName: callSite.getMethodName(),
      fileName: callSite.getFileName(),
      lineNumber: callSite.getLineNumber(),
      columnNumber: callSite.getColumnNumber(),
      evalOrigin: callSite.getEvalOrigin(),
      isToplevel: callSite.isToplevel(),
      isEval: callSite.isEval(),
      isNative: callSite.isNative(),
      isConstructor: callSite.isConstructor(),
      isAsync: callSite.isAsync(),
      isPromiseAll: callSite.isPromiseAll(),
      promiseIndex: callSite.getPromiseIndex(),
    };
  }

  /**
   * Returns a function that can be used as `Error.prepareStackTrace`.
   * 
   * This function accepts an optional argument, a function that performs
   * source mapping. It is not required to pass this argument, but
   * in such case only JavaScript sources will have proper position in
   * stack frames.
   * @param {(
   *  fileName: string,
   *  lineNumber: number,
   *  columnNumber: number
   * ) => {
   *  fileName: string,
   *  lineNumber: number,
   *  columnNumber: number
   * }} sourceMappingFn 
   */
  function createPrepareStackTrace(sourceMappingFn) {
    return function prepareStackTrace(
      error,
      callSites,
    ) {
      const mappedCallSites = callSites.map(
        (callSite) => {
          const fileName = callSite.getFileName();
          const lineNumber = callSite.getLineNumber();
          const columnNumber = callSite.getColumnNumber();
          if (
            sourceMappingFn && fileName && lineNumber != null &&
            columnNumber != null
          ) {
            return patchCallSite(
              callSite,
              sourceMappingFn({
                fileName,
                lineNumber,
                columnNumber,
              }),
            );
          }
          return callSite;
        },
      );
      Object.defineProperties(error, {
        __callSiteEvals: { value: [], configurable: true },
      });
      const formattedCallSites = [];
      for (const callSite of mappedCallSites) {
        error.__callSiteEvals.push(evaluateCallSite(callSite));
        formattedCallSites.push(formatCallSite(callSite));
      }
      const message = error.message !== undefined ? error.message : "";
      const name = error.name !== undefined ? error.name : "Error";
      let messageLine;
      if (name != "" && message != "") {
        messageLine = `${name}: ${message}`;
      } else if ((name || message) != "") {
        messageLine = name || message;
      } else {
        messageLine = "";
      }
      return messageLine +
        formattedCallSites.map((s) => `\n    at ${s}`).join("");
    };
  }

  Object.assign(window.Deno.core, {
    createPrepareStackTrace,
  });
})(this);