diff --git a/README.md b/README.md
index 8fb4d76d..d711f58c 100644
--- a/README.md
+++ b/README.md
@@ -61,21 +61,8 @@ fs.src(['*.js', '!b*.js'])
 
 #### Options
 
-##### `options.cwd`
-
-The working directory the folder is relative to.
-
-Type: `String`
-
-Default: `process.cwd()`
-
-##### `options.base`
-
-The folder relative to the cwd. This is used to determine the file names when saving in `.dest()`.
-
-Type: `String`
-
-Default: The part of the path before the glob (if any) begins. For example, `path/to/**/*.js` would resolve to `path/to`. If there is no glob (i.e. a file path with no pattern), then the dirname of the path is used. For example, `path/to/some/file.js` would resolve to `path/to/some`.
+- Values passed to the options must be of the right type, otherwise they will be ignored.
+- All options can be passed a function instead of a value. The function must return a value of the right type, otherwise it will be ignored.
 
 ##### `options.buffer`
 
@@ -145,6 +132,7 @@ Default: `false`
 
 Any glob-related options are documented in [glob-stream] and [node-glob].
 Any through2-related options are documented in [through2].
+Those options are forwarded verbatim.
 
 ### `dest(folder[, options])`
 
@@ -165,6 +153,9 @@ __Note: The file will be modified after being written to this stream.__
 
 #### Options
 
+- Values passed to the options must be of the right type, otherwise they will be ignored.
+- All options can be passed a function instead of a value. The function will be called with the [vinyl] `File` object as its only argument and must return a value of the right type for the option.
+
 ##### `options.cwd`
 
 The working directory the folder is relative to.
@@ -240,6 +231,7 @@ Default: `undefined` (do not write sourcemaps)
 ##### other
 
 Any through2-related options are documented in [through2].
+Those options are forwarded verbatim.
 
 ### `symlink(folder[, options])`
 
@@ -251,6 +243,9 @@ __Note: The file will be modified after being written to this stream.__
 
 #### Options
 
+- Values passed to the options must be of the right type, otherwise they will be ignored.
+- All options can be passed a function instead of a value. The function will be called with the [vinyl] `File` object as its only argument and must return a value of the right type for the option.
+
 ##### `options.cwd`
 
 The working directory the folder is relative to.
@@ -278,6 +273,7 @@ Default: The process mode.
 ##### other
 
 Any through2-related options are documented in [through2].
+Those options are forwarded verbatim.
 
 [glob-stream]: https://github.com/gulpjs/glob-stream
 [gulp-sourcemaps]: https://github.com/floridoo/gulp-sourcemaps
diff --git a/lib/default-value.js b/lib/default-value.js
new file mode 100644
index 00000000..07eaa0eb
--- /dev/null
+++ b/lib/default-value.js
@@ -0,0 +1,5 @@
+'use strict';
+
+module.exports = function defaultValue(defaultValue, value) {
+  return value === null ? defaultValue : value;
+};
diff --git a/lib/dest/index.js b/lib/dest/index.js
index a25d316f..776d4a48 100644
--- a/lib/dest/index.js
+++ b/lib/dest/index.js
@@ -3,6 +3,8 @@
 var through2 = require('through2');
 var sourcemaps = require('gulp-sourcemaps');
 var duplexify = require('duplexify');
+var valueOrFunction = require('value-or-function');
+
 var sink = require('../sink');
 var prepareWrite = require('../prepare-write');
 var writeContents = require('./write-contents');
@@ -12,6 +14,9 @@ function dest(outFolder, opt) {
     opt = {};
   }
 
+  var sourcemapsOpt = valueOrFunction(
+      ['boolean', 'string', 'object'], opt.sourcemaps);
+
   function saveFile(file, enc, cb) {
     prepareWrite(outFolder, file, opt, function(err, writePath) {
       if (err) {
@@ -22,7 +27,7 @@ function dest(outFolder, opt) {
   }
 
   var saveStream = through2.obj(opt, saveFile);
-  if (!opt.sourcemaps) {
+  if (!sourcemapsOpt) {
     // Sink the save stream to start flowing
     // Do this on nextTick, it will flow at slowest speed of piped streams
     process.nextTick(sink(saveStream));
@@ -30,17 +35,15 @@ function dest(outFolder, opt) {
     return saveStream;
   }
 
-  var sourcemapOpt = opt.sourcemaps;
-  if (typeof sourcemapOpt === 'boolean') {
-    sourcemapOpt = {};
-  }
-  if (typeof sourcemapOpt === 'string') {
-    sourcemapOpt = {
-      path: sourcemapOpt,
+  if (typeof sourcemapsOpt === 'boolean') {
+    sourcemapsOpt = {};
+  } else if (typeof sourcemapsOpt === 'string') {
+    sourcemapsOpt = {
+      path: sourcemapsOpt,
     };
   }
 
-  var mapStream = sourcemaps.write(sourcemapOpt.path, sourcemapOpt);
+  var mapStream = sourcemaps.write(sourcemapsOpt.path, sourcemapsOpt);
   var outputStream = duplexify.obj(mapStream, saveStream);
   mapStream.pipe(saveStream);
 
diff --git a/lib/prepare-write.js b/lib/prepare-write.js
index 50d86cd1..e6f2aa89 100644
--- a/lib/prepare-write.js
+++ b/lib/prepare-write.js
@@ -5,39 +5,34 @@ var path = require('path');
 var mkdirp = require('mkdirp');
 var fs = require('graceful-fs');
 
-function booleanOrFunc(v, file) {
-  if (typeof v !== 'boolean' && typeof v !== 'function') {
-    return null;
-  }
+var valueOrFunction = require('value-or-function');
+var defaultValue = require('./default-value');
 
-  return typeof v === 'boolean' ? v : v(file);
-}
+var boolean = valueOrFunction.boolean;
+var number = valueOrFunction.number;
+var string = valueOrFunction.string;
 
-function stringOrFunc(v, file) {
-  if (typeof v !== 'string' && typeof v !== 'function') {
-    return null;
+function prepareWrite(outFolder, file, opt, cb) {
+  if (!opt) {
+    opt = {};
   }
 
-  return typeof v === 'string' ? v : v(file);
-}
-
-function prepareWrite(outFolder, file, opt, cb) {
-  var options = assign({
-    cwd: process.cwd(),
-    mode: (file.stat ? file.stat.mode : null),
-    dirMode: null,
-    overwrite: true,
-  }, opt);
-  var overwrite = booleanOrFunc(options.overwrite, file);
-  options.flag = (overwrite ? 'w' : 'wx');
+  var defaultMode = file.stat ? file.stat.mode : null;
+  var options = assign({}, opt, {
+    cwd: defaultValue(process.cwd(), string(opt.cwd, file)),
+    base: string(opt.base, file),
+    mode: defaultValue(defaultMode, number(opt.mode, file)),
+    dirMode: number(opt.dirMode, file),
+    overwrite: defaultValue(true, boolean(opt.overwrite, file)),
+  });
+  options.flag = (options.overwrite ? 'w' : 'wx');
 
   var cwd = path.resolve(options.cwd);
-  var outFolderPath = stringOrFunc(outFolder, file);
+  var outFolderPath = string(outFolder, file);
   if (!outFolderPath) {
     throw new Error('Invalid output folder');
   }
-  var basePath = options.base ?
-    stringOrFunc(options.base, file) : path.resolve(cwd, outFolderPath);
+  var basePath = options.base || path.resolve(cwd, outFolderPath);
   if (!basePath) {
     throw new Error('Invalid base option');
   }
diff --git a/lib/src/index.js b/lib/src/index.js
index 9da0c265..6844c314 100644
--- a/lib/src/index.js
+++ b/lib/src/index.js
@@ -6,21 +6,31 @@ var gs = require('glob-stream');
 var duplexify = require('duplexify');
 var merge = require('merge-stream');
 var sourcemaps = require('gulp-sourcemaps');
-var filterSince = require('../filter-since');
 var isValidGlob = require('is-valid-glob');
+var valueOrFunction = require('value-or-function');
 
+var defaultValue = require('../default-value');
+var filterSince = require('../filter-since');
 var getContents = require('./get-contents');
 var wrapWithVinylFile = require('./wrap-with-vinyl-file');
 
+var boolean = valueOrFunction.boolean;
+var date = valueOrFunction.date;
+
 function src(glob, opt) {
-  var options = assign({
-    read: true,
-    buffer: true,
-    stripBOM: true,
-    sourcemaps: false,
-    passthrough: false,
-    followSymlinks: true,
-  }, opt);
+  if (!opt) {
+    opt = {};
+  }
+
+  var options = assign({}, opt, {
+    buffer: defaultValue(true, boolean(opt.buffer)),
+    read: defaultValue(true, boolean(opt.read)),
+    since: date(opt.since),
+    stripBOM: defaultValue(true, boolean(opt.stripBOM)),
+    sourcemaps: defaultValue(false, boolean(opt.sourcemaps)),
+    passthrough: defaultValue(false, boolean(opt.passthrough)),
+    followSymlinks: defaultValue(true, boolean(opt.followSymlinks)),
+  });
 
   // Don't pass `read` option on to through2
   var read = options.read !== false;
diff --git a/package.json b/package.json
index cca6081b..8fd853a4 100644
--- a/package.json
+++ b/package.json
@@ -27,6 +27,7 @@
     "through2": "^2.0.0",
     "through2-filter": "^2.0.0",
     "vali-date": "^1.0.0",
+    "value-or-function": "^1.2.0",
     "vinyl": "^1.0.0"
   },
   "devDependencies": {
diff --git a/test/default-value.js b/test/default-value.js
new file mode 100644
index 00000000..cabd036d
--- /dev/null
+++ b/test/default-value.js
@@ -0,0 +1,21 @@
+'use strict';
+
+var expect = require('expect');
+
+var defaultValue = require('../lib/default-value');
+
+describe('defaultVaule', function() {
+
+  it('returns the value if the value is not null', function() {
+    expect(defaultValue('defaultValue', 1)).toBe(1);
+  });
+
+  it('returns the value if the value is undefined', function() {
+    expect(defaultValue('defaultValue', undefined)).toBe(undefined);
+  });
+
+  it('returns the default value if the value is null', function() {
+    expect(defaultValue('defaultValue', null)).toBe('defaultValue');
+  });
+
+});
diff --git a/test/src.js b/test/src.js
index 1601e17f..251425e1 100644
--- a/test/src.js
+++ b/test/src.js
@@ -398,10 +398,8 @@ describe('source stream', function() {
 
   it('should not pass options.read on to through2', function(done) {
     // Note: https://github.com/gulpjs/vinyl-fs/issues/153
-    // In future, if/when function values are supported for options like
-    // `read` and `buffered`, the expected value here will be 1.
     var canary = 0;
-    var expected = 0;
+    var expected = 1;
     var read = function() {
       canary++;
       return 0;