node/lib/internal/console/constructor.js

'use strict';

// The Console constructor is not actually used to construct the global
// console. It's exported for backwards compatibility.

const { trace } = internalBinding('trace_events');
const {
  isStackOverflowError,
  codes: {
    ERR_CONSOLE_WRITABLE_STREAM,
    ERR_INVALID_ARG_TYPE,
    ERR_INVALID_ARG_VALUE,
  },
} = require('internal/errors');
const { previewEntries } = internalBinding('util');
const { Buffer: { isBuffer } } = require('buffer');
const util = require('util');
const {
  isTypedArray, isSet, isMap, isSetIterator, isMapIterator,
} = util.types;
const kCounts = Symbol('counts');

const kTraceConsoleCategory = 'node,node.console';
const kTraceCount = 'C'.charCodeAt(0);
const kTraceBegin = 'b'.charCodeAt(0);
const kTraceEnd = 'e'.charCodeAt(0);
const kTraceInstant = 'n'.charCodeAt(0);

const {
  keys: ObjectKeys,
  values: ObjectValues,
} = Object;
const hasOwnProperty = Function.call.bind(Object.prototype.hasOwnProperty);

const {
  isArray: ArrayIsArray,
  from: ArrayFrom,
} = Array;

// Lazy loaded for startup performance.
let cliTable;

// Track amount of indentation required via `console.group()`.
const kGroupIndent = Symbol('kGroupIndent');
const kFormatForStderr = Symbol('kFormatForStderr');
const kFormatForStdout = Symbol('kFormatForStdout');
const kGetInspectOptions = Symbol('kGetInspectOptions');
const kColorMode = Symbol('kColorMode');
const kIsConsole = Symbol('kIsConsole');
const kWriteToConsole = Symbol('kWriteToConsole');
const kBindProperties = Symbol('kBindProperties');
const kBindStreamsEager = Symbol('kBindStreamsEager');
const kBindStreamsLazy = Symbol('kBindStreamsLazy');
const kUseStdout = Symbol('kUseStdout');
const kUseStderr = Symbol('kUseStderr');

function Console(options /* or: stdout, stderr, ignoreErrors = true */) {
  // We have to test new.target here to see if this function is called
  // with new, because we need to define a custom instanceof to accommodate
  // the global console.
  if (!new.target) {
    return new Console(...arguments);
  }

  if (!options || typeof options.write === 'function') {
    options = {
      stdout: options,
      stderr: arguments[1],
      ignoreErrors: arguments[2]
    };
  }

  const {
    stdout,
    stderr = stdout,
    ignoreErrors = true,
    colorMode = 'auto'
  } = options;

  if (!stdout || typeof stdout.write !== 'function') {
    throw new ERR_CONSOLE_WRITABLE_STREAM('stdout');
  }
  if (!stderr || typeof stderr.write !== 'function') {
    throw new ERR_CONSOLE_WRITABLE_STREAM('stderr');
  }

  if (typeof colorMode !== 'boolean' && colorMode !== 'auto')
    throw new ERR_INVALID_ARG_VALUE('colorMode', colorMode);

  // bind the prototype functions to this Console instance
  var keys = Object.keys(Console.prototype);
  for (var v = 0; v < keys.length; v++) {
    var k = keys[v];
    // We have to bind the methods grabbed from the instance instead of from
    // the prototype so that users extending the Console can override them
    // from the prototype chain of the subclass.
    this[k] = this[k].bind(this);
  }

  this[kBindStreamsEager](stdout, stderr);
  this[kBindProperties](ignoreErrors, colorMode);
}

const consolePropAttributes = {
  writable: true,
  enumerable: false,
  configurable: true
};

// Fixup global.console instanceof global.console.Console
Object.defineProperty(Console, Symbol.hasInstance, {
  value(instance) {
    return instance[kIsConsole];
  }
});

// Eager version for the Console constructor
Console.prototype[kBindStreamsEager] = function(stdout, stderr) {
  Object.defineProperties(this, {
    '_stdout': { ...consolePropAttributes, value: stdout },
    '_stderr': { ...consolePropAttributes, value: stderr }
  });
};

// Lazily load the stdout and stderr from an object so we don't
// create the stdio streams when they are not even accessed
Console.prototype[kBindStreamsLazy] = function(object) {
  let stdout;
  let stderr;
  Object.defineProperties(this, {
    '_stdout': {
      enumerable: false,
      configurable: true,
      get() {
        if (!stdout) stdout = object.stdout;
        return stdout;
      },
      set(value) { stdout = value; }
    },
    '_stderr': {
      enumerable: false,
      configurable: true,
      get() {
        if (!stderr) { stderr = object.stderr; }
        return stderr;
      },
      set(value) { stderr = value; }
    }
  });
};

Console.prototype[kBindProperties] = function(ignoreErrors, colorMode) {
  Object.defineProperties(this, {
    '_stdoutErrorHandler': {
      ...consolePropAttributes,
      value: createWriteErrorHandler(this, kUseStdout)
    },
    '_stderrErrorHandler': {
      ...consolePropAttributes,
      value: createWriteErrorHandler(this, kUseStderr)
    },
    '_ignoreErrors': {
      ...consolePropAttributes,
      value: Boolean(ignoreErrors)
    },
    '_times': { ...consolePropAttributes, value: new Map() }
  });

  // TODO(joyeecheung): use consolePropAttributes for these
  // Corresponds to https://console.spec.whatwg.org/#count-map
  this[kCounts] = new Map();
  this[kColorMode] = colorMode;
  this[kIsConsole] = true;
  this[kGroupIndent] = '';
};

// Make a function that can serve as the callback passed to `stream.write()`.
function createWriteErrorHandler(instance, streamSymbol) {
  return (err) => {
    // This conditional evaluates to true if and only if there was an error
    // that was not already emitted (which happens when the _write callback
    // is invoked asynchronously).
    const stream = streamSymbol === kUseStdout ?
      instance._stdout : instance._stderr;
    if (err !== null && !stream._writableState.errorEmitted) {
      // If there was an error, it will be emitted on `stream` as
      // an `error` event. Adding a `once` listener will keep that error
      // from becoming an uncaught exception, but since the handler is
      // removed after the event, non-console.* writes won't be affected.
      // we are only adding noop if there is no one else listening for 'error'
      if (stream.listenerCount('error') === 0) {
        stream.on('error', noop);
      }
    }
  };
}

Console.prototype[kWriteToConsole] = function(streamSymbol, string) {
  const ignoreErrors = this._ignoreErrors;
  const groupIndent = this[kGroupIndent];

  const useStdout = streamSymbol === kUseStdout;
  const stream = useStdout ? this._stdout : this._stderr;
  const errorHandler = useStdout ?
    this._stdoutErrorHandler : this._stderrErrorHandler;

  if (groupIndent.length !== 0) {
    if (string.indexOf('\n') !== -1) {
      string = string.replace(/\n/g, `\n${groupIndent}`);
    }
    string = groupIndent + string;
  }
  string += '\n';

  if (ignoreErrors === false) return stream.write(string);

  // There may be an error occurring synchronously (e.g. for files or TTYs
  // on POSIX systems) or asynchronously (e.g. pipes on POSIX systems), so
  // handle both situations.
  try {
    // Add and later remove a noop error handler to catch synchronous errors.
    stream.once('error', noop);

    stream.write(string, errorHandler);
  } catch (e) {
    // console is a debugging utility, so it swallowing errors is not desirable
    // even in edge cases such as low stack space.
    if (isStackOverflowError(e))
      throw e;
    // Sorry, there's no proper way to pass along the error here.
  } finally {
    stream.removeListener('error', noop);
  }
};

const kColorInspectOptions = { colors: true };
const kNoColorInspectOptions = {};
Console.prototype[kGetInspectOptions] = function(stream) {
  let color = this[kColorMode];
  if (color === 'auto') {
    color = stream.isTTY && (
      typeof stream.getColorDepth === 'function' ?
        stream.getColorDepth() > 2 : true);
  }

  return color ? kColorInspectOptions : kNoColorInspectOptions;
};

Console.prototype[kFormatForStdout] = function(args) {
  const opts = this[kGetInspectOptions](this._stdout);
  return util.formatWithOptions(opts, ...args);
};

Console.prototype[kFormatForStderr] = function(args) {
  const opts = this[kGetInspectOptions](this._stderr);
  return util.formatWithOptions(opts, ...args);
};

Console.prototype.log = function log(...args) {
  this[kWriteToConsole](kUseStdout, this[kFormatForStdout](args));
};

Console.prototype.debug = Console.prototype.log;
Console.prototype.info = Console.prototype.log;
Console.prototype.dirxml = Console.prototype.log;

Console.prototype.warn = function warn(...args) {
  this[kWriteToConsole](kUseStderr, this[kFormatForStderr](args));
};

Console.prototype.error = Console.prototype.warn;

Console.prototype.dir = function dir(object, options) {
  options = Object.assign({
    customInspect: false
  }, this[kGetInspectOptions](this._stdout), options);
  this[kWriteToConsole](kUseStdout, util.inspect(object, options));
};

Console.prototype.time = function time(label = 'default') {
  // Coerces everything other than Symbol to a string
  label = `${label}`;
  if (this._times.has(label)) {
    process.emitWarning(`Label '${label}' already exists for console.time()`);
    return;
  }
  trace(kTraceBegin, kTraceConsoleCategory, `time::${label}`, 0);
  this._times.set(label, process.hrtime());
};

Console.prototype.timeEnd = function timeEnd(label = 'default') {
  // Coerces everything other than Symbol to a string
  label = `${label}`;
  const hasWarned = timeLogImpl(this, 'timeEnd', label);
  trace(kTraceEnd, kTraceConsoleCategory, `time::${label}`, 0);
  if (!hasWarned) {
    this._times.delete(label);
  }
};

Console.prototype.timeLog = function timeLog(label = 'default', ...data) {
  // Coerces everything other than Symbol to a string
  label = `${label}`;
  timeLogImpl(this, 'timeLog', label, data);
  trace(kTraceInstant, kTraceConsoleCategory, `time::${label}`, 0);
};

// Returns true if label was not found
function timeLogImpl(self, name, label, data) {
  const time = self._times.get(label);
  if (!time) {
    process.emitWarning(`No such label '${label}' for console.${name}()`);
    return true;
  }
  const duration = process.hrtime(time);
  const ms = duration[0] * 1000 + duration[1] / 1e6;
  if (data === undefined) {
    self.log('%s: %sms', label, ms.toFixed(3));
  } else {
    self.log('%s: %sms', label, ms.toFixed(3), ...data);
  }
  return false;
}

Console.prototype.trace = function trace(...args) {
  const err = {
    name: 'Trace',
    message: this[kFormatForStderr](args)
  };
  Error.captureStackTrace(err, trace);
  this.error(err.stack);
};

Console.prototype.assert = function assert(expression, ...args) {
  if (!expression) {
    args[0] = `Assertion failed${args.length === 0 ? '' : `: ${args[0]}`}`;
    this.warn(...args);  // the arguments will be formatted in warn() again
  }
};

// Defined by: https://console.spec.whatwg.org/#clear
Console.prototype.clear = function clear() {
  // It only makes sense to clear if _stdout is a TTY.
  // Otherwise, do nothing.
  if (this._stdout.isTTY) {
    // The require is here intentionally to avoid readline being
    // required too early when console is first loaded.
    const { cursorTo, clearScreenDown } = require('readline');
    cursorTo(this._stdout, 0, 0);
    clearScreenDown(this._stdout);
  }
};

// Defined by: https://console.spec.whatwg.org/#count
Console.prototype.count = function count(label = 'default') {
  // Ensures that label is a string, and only things that can be
  // coerced to strings. e.g. Symbol is not allowed
  label = `${label}`;
  const counts = this[kCounts];
  let count = counts.get(label);
  if (count === undefined)
    count = 1;
  else
    count++;
  counts.set(label, count);
  trace(kTraceCount, kTraceConsoleCategory, `count::${label}`, 0, count);
  this.log(`${label}: ${count}`);
};

// Defined by: https://console.spec.whatwg.org/#countreset
Console.prototype.countReset = function countReset(label = 'default') {
  const counts = this[kCounts];
  if (!counts.has(label)) {
    process.emitWarning(`Count for '${label}' does not exist`);
    return;
  }
  trace(kTraceCount, kTraceConsoleCategory, `count::${label}`, 0, 0);
  counts.delete(`${label}`);
};

Console.prototype.group = function group(...data) {
  if (data.length > 0) {
    this.log(...data);
  }
  this[kGroupIndent] += '  ';
};
Console.prototype.groupCollapsed = Console.prototype.group;

Console.prototype.groupEnd = function groupEnd() {
  this[kGroupIndent] =
    this[kGroupIndent].slice(0, this[kGroupIndent].length - 2);
};

const keyKey = 'Key';
const valuesKey = 'Values';
const indexKey = '(index)';
const iterKey = '(iteration index)';

const isArray = (v) => ArrayIsArray(v) || isTypedArray(v) || isBuffer(v);

// https://console.spec.whatwg.org/#table
Console.prototype.table = function(tabularData, properties) {
  if (properties !== undefined && !ArrayIsArray(properties))
    throw new ERR_INVALID_ARG_TYPE('properties', 'Array', properties);

  if (tabularData === null || typeof tabularData !== 'object')
    return this.log(tabularData);

  if (cliTable === undefined) cliTable = require('internal/cli_table');
  const final = (k, v) => this.log(cliTable(k, v));

  const inspect = (v) => {
    const opt = { depth: 0, maxArrayLength: 3 };
    if (v !== null && typeof v === 'object' &&
      !isArray(v) && ObjectKeys(v).length > 2)
      opt.depth = -1;
    Object.assign(opt, this[kGetInspectOptions](this._stdout));
    return util.inspect(v, opt);
  };
  const getIndexArray = (length) => ArrayFrom({ length }, (_, i) => inspect(i));

  const mapIter = isMapIterator(tabularData);
  let isKeyValue = false;
  let i = 0;
  if (mapIter) {
    const res = previewEntries(tabularData, true);
    tabularData = res[0];
    isKeyValue = res[1];
  }

  if (isKeyValue || isMap(tabularData)) {
    const keys = [];
    const values = [];
    let length = 0;
    if (mapIter) {
      for (; i < tabularData.length / 2; ++i) {
        keys.push(inspect(tabularData[i * 2]));
        values.push(inspect(tabularData[i * 2 + 1]));
        length++;
      }
    } else {
      for (const [k, v] of tabularData) {
        keys.push(inspect(k));
        values.push(inspect(v));
        length++;
      }
    }
    return final([
      iterKey, keyKey, valuesKey
    ], [
      getIndexArray(length),
      keys,
      values,
    ]);
  }

  const setIter = isSetIterator(tabularData);
  if (setIter)
    tabularData = previewEntries(tabularData);

  const setlike = setIter || (mapIter && !isKeyValue) || isSet(tabularData);
  if (setlike) {
    const values = [];
    let length = 0;
    for (const v of tabularData) {
      values.push(inspect(v));
      length++;
    }
    return final([setlike ? iterKey : indexKey, valuesKey], [
      getIndexArray(length),
      values,
    ]);
  }

  const map = {};
  let hasPrimitives = false;
  const valuesKeyArray = [];
  const indexKeyArray = ObjectKeys(tabularData);

  for (; i < indexKeyArray.length; i++) {
    const item = tabularData[indexKeyArray[i]];
    const primitive = item === null ||
        (typeof item !== 'function' && typeof item !== 'object');
    if (properties === undefined && primitive) {
      hasPrimitives = true;
      valuesKeyArray[i] = inspect(item);
    } else {
      const keys = properties || ObjectKeys(item);
      for (const key of keys) {
        if (map[key] === undefined)
          map[key] = [];
        if ((primitive && properties) || !hasOwnProperty(item, key))
          map[key][i] = '';
        else
          map[key][i] = item == null ? item : inspect(item[key]);
      }
    }
  }

  const keys = ObjectKeys(map);
  const values = ObjectValues(map);
  if (hasPrimitives) {
    keys.push(valuesKey);
    values.push(valuesKeyArray);
  }
  keys.unshift(indexKey);
  values.unshift(indexKeyArray);

  return final(keys, values);
};

function noop() {}

module.exports = {
  Console,
  kBindStreamsLazy,
  kBindProperties
};