diff --git a/API.md b/API.md
index 515e53da..9776c74a 100755
--- a/API.md
+++ b/API.md
@@ -7,15 +7,11 @@
   * [applyToDefaults](#applytodefaultsdefaults-options-isnulloverride "applyToDefaults")
   * [applyToDefaultsWithShallow](#applytodefaultswithshallowdefaults-options-keys "applyToDefaultsWithShallow")
   * [deepEqual](#deepequalb-a-options "deepEqual")
-  * [unique](#uniquearray-key "unique")
-  * [mapToObject](#maptoobjectarray-key "mapToObject")
   * [intersect](#intersectarray1-array2 "intersect")
   * [contain](#containref-values-options "contain")
   * [flatten](#flattenarray-target "flatten")
   * [reach](#reachobj-chain-options "reach")
   * [reachTemplate](#reachtemplateobj-template-options "reachTemplate")
-  * [transform](#transformobj-transform-options "transform")
-  * [shallow](#shallowsource "shallow")
   * [stringify](#stringifyobj "stringify")
 * [Bench](#bench "Bench")
 * [Escaping Characters](#escaping-characters "Escaping Characters")
@@ -170,34 +166,6 @@ Hoek.deepEqual(Object.create(null), {}, { prototype: false }); //results in true
 Hoek.deepEqual(Object.create(null), {}); //results in false
 ```
 
-### unique(array, key)
-
-Remove duplicate items from Array
-
-```javascript
-
-var array = [1, 2, 2, 3, 3, 4, 5, 6];
-
-var newArray = Hoek.unique(array);    // results in [1,2,3,4,5,6]
-
-array = [{id: 1}, {id: 1}, {id: 2}];
-
-newArray = Hoek.unique(array, "id");  // results in [{id: 1}, {id: 2}]
-```
-
-### mapToObject(array, key)
-
-Convert an Array into an Object
-
-```javascript
-
-var array = [1,2,3];
-var newObject = Hoek.mapToObject(array);   // results in {"1": true, "2": true, "3": true}
-
-array = [{id: 1}, {id: 2}];
-newObject = Hoek.mapToObject(array, "id"); // results in {"1": true, "2": true}
-```
-
 ### intersect(array1, array2)
 
 Find the common unique items in two arrays
@@ -293,48 +261,6 @@ var obj = {a : {b : { c : 1}}};
 Hoek.reachTemplate(obj, '1+{a.b.c}=2'); // returns '1+1=2'
 ```
 
-### transform(obj, transform, [options])
-
-Transforms an existing object into a new one based on the supplied `obj` and `transform` map. `options` are the same as the `reach` options. The first argument can also be an array of objects. In that case the method will return an array of transformed objects. Note that `options.separator` will be respected for the keys in the transform object as well as values.
-
-```javascript
-var source = {
-    address: {
-        one: '123 main street',
-        two: 'PO Box 1234'
-    },
-    title: 'Warehouse',
-    state: 'CA'
-};
-
-var result = Hoek.transform(source, {
-    'person.address.lineOne': 'address.one',
-    'person.address.lineTwo': 'address.two',
-    'title': 'title',
-    'person.address.region': 'state'
-});
-// Results in
-// {
-//     person: {
-//         address: {
-//             lineOne: '123 main street',
-//             lineTwo: 'PO Box 1234',
-//             region: 'CA'
-//         }
-//     },
-//     title: 'Warehouse'
-// }
-```
-
-### shallow(source)
-
-Returns a new object with shallow copies of all source properties where:
-- `source` - the source to be copied.
-
-```javascript
-var shallow = Hoek.shallow({ a: { b: 1 } });
-```
-
 ### stringify(obj)
 
 Converts an object to string using the built-in `JSON.stringify()` method with the difference that any errors are caught
diff --git a/README.md b/README.md
old mode 100644
new mode 100755
index a5c05086..dba9868e
--- a/README.md
+++ b/README.md
@@ -1,25 +1,14 @@
 ![hoek Logo](https://raw.github.com/hapijs/hoek/master/images/hoek.png)
 
-Utility methods for the hapi ecosystem. This module is not intended to solve every problem for everyone, but rather as a central place to store hapi-specific methods. If you're looking for a general purpose utility module, check out [lodash](https://github.com/lodash/lodash) or [underscore](https://github.com/jashkenas/underscore).
+Utility methods for the hapi ecosystem. This module is not intended to solve every problem for
+everyone, but rather as a central place to store hapi-specific methods. If you're looking for a
+general purpose utility module, check out [lodash](https://github.com/lodash/lodash) or
+[underscore](https://github.com/jashkenas/underscore).
 
 [![Build Status](https://secure.travis-ci.org/hapijs/hoek.svg)](http://travis-ci.org/hapijs/hoek)
 
 Lead Maintainer: [Gil Pedersen](https://github.com/kanongil)
 
-## Usage
-
-The *Hoek* library contains some common functions used within the hapi ecosystem. It comes with useful methods for Arrays (clone, merge, applyToDefaults), Objects (removeKeys, copy), Asserting and more.
-
-For example, to use Hoek to set configuration with default options:
-```javascript
-const Hoek = require('hoek');
-
-const default = {url : "www.github.com", port : "8000", debug : true};
-
-const config = Hoek.applyToDefaults(default, {port : "3000", admin : true});
-
-// In this case, config would be { url: 'www.github.com', port: '3000', debug: true, admin: true }
-```
 
 ## Documentation
 
diff --git a/lib/index.js b/lib/index.js
index 717759b3..2bdcdde8 100755
--- a/lib/index.js
+++ b/lib/index.js
@@ -371,78 +371,43 @@ exports.deepEqual = function (obj, ref, options, seen) {
 };
 
 
-// Remove duplicate items from array
+// Find the common unique items in two arrays
 
-exports.unique = (array, key) => {
+exports.intersect = function (array1, array2, justFirst) {
 
-    let result;
-    if (key) {
-        result = [];
-        const index = new Set();
-        array.forEach((item) => {
+    if (!array1 ||
+        !array2) {
 
-            const identifier = item[key];
-            if (!index.has(identifier)) {
-                index.add(identifier);
-                result.push(item);
-            }
-        });
-    }
-    else {
-        result = Array.from(new Set(array));
+        return (justFirst ? null : []);
     }
 
-    return result;
-};
-
-
-// Convert array into object
-
-exports.mapToObject = function (array, key) {
-
-    if (!array) {
-        return null;
-    }
+    const common = [];
+    const hash = (Array.isArray(array1) ? new Set(array1) : array1);
+    const found = new Set();
+    for (const value of array2) {
+        if (internals.has(hash, value) &&
+            !found.has(value)) {
 
-    const obj = {};
-    for (let i = 0; i < array.length; ++i) {
-        if (key) {
-            if (array[i][key]) {
-                obj[array[i][key]] = true;
+            if (justFirst) {
+                return value;
             }
-        }
-        else {
-            obj[array[i]] = true;
+
+            common.push(value);
+            found.add(value);
         }
     }
 
-    return obj;
+    return (justFirst ? null : common);
 };
 
 
-// Find the common unique items in two arrays
-
-exports.intersect = function (array1, array2, justFirst) {
-
-    if (!array1 || !array2) {
-        return [];
-    }
-
-    const common = [];
-    const hash = (Array.isArray(array1) ? exports.mapToObject(array1) : array1);
-    const found = {};
-    for (let i = 0; i < array2.length; ++i) {
-        if (hash[array2[i]] && !found[array2[i]]) {
-            if (justFirst) {
-                return array2[i];
-            }
+internals.has = function (ref, key) {
 
-            common.push(array2[i]);
-            found[array2[i]] = true;
-        }
+    if (typeof ref.has === 'function') {
+        return ref.has(key);
     }
 
-    return (justFirst ? null : common);
+    return ref[key] !== undefined;
 };
 
 
@@ -751,50 +716,6 @@ exports.once = function (method) {
 exports.ignore = function () { };
 
 
-exports.transform = function (source, transform, options) {
-
-    exports.assert(source === null || source === undefined || typeof source === 'object' || Array.isArray(source), 'Invalid source object: must be null, undefined, an object, or an array');
-    const separator = (typeof options === 'object' && options !== null) ? (options.separator || '.') : '.';
-
-    if (Array.isArray(source)) {
-        const results = [];
-        for (let i = 0; i < source.length; ++i) {
-            results.push(exports.transform(source[i], transform, options));
-        }
-
-        return results;
-    }
-
-    const result = {};
-    const keys = Object.keys(transform);
-
-    for (let i = 0; i < keys.length; ++i) {
-        const key = keys[i];
-        const path = key.split(separator);
-        const sourcePath = transform[key];
-
-        exports.assert(typeof sourcePath === 'string', 'All mappings must be "." delineated strings');
-
-        let segment;
-        let res = result;
-
-        while (path.length > 1) {
-            segment = path.shift();
-            if (!res[segment]) {
-                res[segment] = {};
-            }
-
-            res = res[segment];
-        }
-
-        segment = path.shift();
-        res[segment] = exports.reach(source, sourcePath, options);
-    }
-
-    return result;
-};
-
-
 exports.uniqueFilename = function (path, extension) {
 
     if (extension) {
@@ -821,12 +742,6 @@ exports.stringify = function (...args) {
 };
 
 
-exports.shallow = function (source) {
-
-    return Object.assign({}, source);
-};
-
-
 exports.wait = function (timeout) {
 
     return new Promise((resolve) => setTimeout(resolve, timeout));
diff --git a/test/index.js b/test/index.js
index 116727ff..70267652 100755
--- a/test/index.js
+++ b/test/index.js
@@ -35,38 +35,6 @@ const nestedObj = {
     z: new Date(1378775452757)
 };
 
-internals.unique = {
-    item: {
-        objects: [nestedObj, { z: 'z' }]
-    }
-};
-
-internals.unique.objectsByKey = {
-    dups: [internals.unique.item.objects[0], internals.unique.item.objects[1], internals.unique.item.objects[0]],
-    result: [internals.unique.item.objects[0], internals.unique.item.objects[1]]
-};
-
-internals.unique.objects = {
-    dups: [internals.unique.item.objects[1], internals.unique.item.objects[0], internals.unique.item.objects[0]],
-    result: [internals.unique.item.objects[1], internals.unique.item.objects[0]]
-};
-
-internals.unique.integers = {
-    dups: [1, 2, 3, 2, 2, 1, 3, 4, 5],
-    result: [1, 2, 3, 4, 5]
-};
-
-internals.unique.strings = {
-    dups: ['a', 'b', 'c', 'd', 'a', 'c', 'e'],
-    result: ['a', 'b', 'c', 'd', 'e']
-};
-
-internals.unique.mixed = {
-    dups: [1, 2, 'a', 'b', internals.unique.item.objects[0], 'a', '2', 3, internals.unique.item.objects[0]],
-    result: [1, 2, 'a', ',b', internals.unique.item.objects[0], 3]
-};
-
-
 describe('clone()', () => {
 
     it('clones a nested object', () => {
@@ -1215,75 +1183,6 @@ describe('deepEqual()', () => {
     });
 });
 
-describe('unique()', () => {
-
-    const deprecatedUnique = function (array, key) { // previous method of unique from hapi 3.0.4
-
-        const index = {};
-        const result = [];
-
-        for (let i = 0; i < array.length; ++i) {
-            const id = (key ? array[i][key] : array[i]);
-            if (index[id] !== true) {
-
-                result.push(array[i]);
-                index[id] = true;
-            }
-        }
-
-        return result;
-    };
-
-    it('ensures uniqueness within array of objects based on subkey', () => {
-
-        expect(Hoek.unique(internals.unique.objectsByKey.dups, 'x')).to.equal(internals.unique.objectsByKey.result);
-        expect(deprecatedUnique(internals.unique.objectsByKey.dups, 'x')).to.equal(internals.unique.objectsByKey.result);
-
-    });
-
-    it('removes duplicated integers without key', () => {
-
-        expect(Hoek.unique(internals.unique.integers.dups)).to.equal(internals.unique.integers.result);
-        expect(deprecatedUnique(internals.unique.integers.dups)).to.equal(internals.unique.integers.result);
-    });
-
-    it('removes duplicated strings without key', () => {
-
-        expect(Hoek.unique(internals.unique.strings.dups)).to.equal(internals.unique.strings.result);
-        expect(deprecatedUnique(internals.unique.strings.dups)).to.equal(internals.unique.strings.result);
-    });
-
-    it('removes duplicated objects without key', () => { // this was not supported in earlier versions
-
-        expect(Hoek.unique(internals.unique.objects.dups)).to.equal(internals.unique.objects.result);
-        expect(deprecatedUnique(internals.unique.objects.dups)).to.not.equal(internals.unique.objects.result);
-    });
-});
-
-describe('mapToObject()', () => {
-
-    it('returns null on null array', () => {
-
-        const a = Hoek.mapToObject(null);
-        expect(a).to.equal(null);
-    });
-
-    it('converts basic array to existential object', () => {
-
-        const keys = [1, 2, 3, 4];
-        const a = Hoek.mapToObject(keys);
-        expect(Object.keys(a)).to.equal(['1', '2', '3', '4']);
-    });
-
-    it('converts array of objects to existential object', () => {
-
-        const keys = [{ x: 1 }, { x: 2 }, { x: 3 }, { y: 4 }];
-        const subkey = 'x';
-        const a = Hoek.mapToObject(keys, subkey);
-        expect(a).to.equal({ 1: true, 2: true, 3: true });
-    });
-});
-
 describe('intersect()', () => {
 
     it('returns the common objects of two arrays', () => {
@@ -1314,13 +1213,14 @@ describe('intersect()', () => {
 
         expect(Hoek.intersect([1], null).length).to.equal(0);
         expect(Hoek.intersect(null, [1]).length).to.equal(0);
+        expect(Hoek.intersect(null, [1], true)).to.be.null();
     });
 
     it('returns the common objects of object and array', () => {
 
-        const array1 = [1, 2, 3, 4, 4, 5, 5];
+        const array1 = { 1: true, 2: true, 3: true, 4: true, 5: true };
         const array2 = [5, 4, 5, 6, 7];
-        const common = Hoek.intersect(Hoek.mapToObject(array1), array2);
+        const common = Hoek.intersect(array1, array2);
         expect(common.length).to.equal(2);
     });
 });
@@ -1821,218 +1721,6 @@ describe('ignore()', () => {
     });
 });
 
-describe('transform()', () => {
-
-    const source = {
-        address: {
-            one: '123 main street',
-            two: 'PO Box 1234'
-        },
-        zip: {
-            code: 3321232,
-            province: null
-        },
-        title: 'Warehouse',
-        state: 'CA'
-    };
-
-    const sourcesArray = [{
-        address: {
-            one: '123 main street',
-            two: 'PO Box 1234'
-        },
-        zip: {
-            code: 3321232,
-            province: null
-        },
-        title: 'Warehouse',
-        state: 'CA'
-    }, {
-        address: {
-            one: '456 market street',
-            two: 'PO Box 5678'
-        },
-        zip: {
-            code: 9876,
-            province: null
-        },
-        title: 'Garage',
-        state: 'NY'
-    }];
-
-    it('transforms an object based on the input object', () => {
-
-        const result = Hoek.transform(source, {
-            'person.address.lineOne': 'address.one',
-            'person.address.lineTwo': 'address.two',
-            'title': 'title',
-            'person.address.region': 'state',
-            'person.address.zip': 'zip.code',
-            'person.address.location': 'zip.province'
-        });
-
-        expect(result).to.equal({
-            person: {
-                address: {
-                    lineOne: '123 main street',
-                    lineTwo: 'PO Box 1234',
-                    region: 'CA',
-                    zip: 3321232,
-                    location: null
-                }
-            },
-            title: 'Warehouse'
-        });
-    });
-
-    it('transforms an array of objects based on the input object', () => {
-
-        const result = Hoek.transform(sourcesArray, {
-            'person.address.lineOne': 'address.one',
-            'person.address.lineTwo': 'address.two',
-            'title': 'title',
-            'person.address.region': 'state',
-            'person.address.zip': 'zip.code',
-            'person.address.location': 'zip.province'
-        });
-
-        expect(result).to.equal([
-            {
-                person: {
-                    address: {
-                        lineOne: '123 main street',
-                        lineTwo: 'PO Box 1234',
-                        region: 'CA',
-                        zip: 3321232,
-                        location: null
-                    }
-                },
-                title: 'Warehouse'
-            },
-            {
-                person: {
-                    address: {
-                        lineOne: '456 market street',
-                        lineTwo: 'PO Box 5678',
-                        region: 'NY',
-                        zip: 9876,
-                        location: null
-                    }
-                },
-                title: 'Garage'
-            }
-        ]);
-    });
-
-    it('uses the reach options passed into it', () => {
-
-        const schema = {
-            'person-address-lineOne': 'address-one',
-            'person-address-lineTwo': 'address-two',
-            'title': 'title',
-            'person-address-region': 'state',
-            'person-prefix': 'person-title',
-            'person-zip': 'zip-code'
-        };
-        const options = {
-            separator: '-',
-            default: 'unknown'
-        };
-        const result = Hoek.transform(source, schema, options);
-
-        expect(result).to.equal({
-            person: {
-                address: {
-                    lineOne: '123 main street',
-                    lineTwo: 'PO Box 1234',
-                    region: 'CA'
-                },
-                prefix: 'unknown',
-                zip: 3321232
-            },
-            title: 'Warehouse'
-        });
-    });
-
-    it('uses a default separator for keys if options does not specify on', () => {
-
-        const schema = {
-            'person.address.lineOne': 'address.one',
-            'person.address.lineTwo': 'address.two',
-            'title': 'title',
-            'person.address.region': 'state',
-            'person.prefix': 'person.title',
-            'person.zip': 'zip.code'
-        };
-        const options = {
-            default: 'unknown'
-        };
-        const result = Hoek.transform(source, schema, options);
-
-        expect(result).to.equal({
-            person: {
-                address: {
-                    lineOne: '123 main street',
-                    lineTwo: 'PO Box 1234',
-                    region: 'CA'
-                },
-                prefix: 'unknown',
-                zip: 3321232
-            },
-            title: 'Warehouse'
-        });
-    });
-
-    it('works to create shallow objects', () => {
-
-        const result = Hoek.transform(source, {
-            lineOne: 'address.one',
-            lineTwo: 'address.two',
-            title: 'title',
-            region: 'state',
-            province: 'zip.province'
-        });
-
-        expect(result).to.equal({
-            lineOne: '123 main street',
-            lineTwo: 'PO Box 1234',
-            title: 'Warehouse',
-            region: 'CA',
-            province: null
-        });
-    });
-
-    it('only allows strings in the map', () => {
-
-        expect(() => {
-
-            Hoek.transform(source, {
-                lineOne: {}
-            });
-        }).to.throw('All mappings must be "." delineated strings');
-    });
-
-    it('throws an error on invalid arguments', () => {
-
-        expect(() => {
-
-            Hoek.transform(NaN, {});
-        }).to.throw('Invalid source object: must be null, undefined, an object, or an array');
-    });
-
-    it('is safe to pass null', () => {
-
-        const result = Hoek.transform(null, {});
-        expect(result).to.equal({});
-    });
-
-    it('is safe to pass undefined', () => {
-
-        const result = Hoek.transform(undefined, {});
-        expect(result).to.equal({});
-    });
-});
-
 describe('uniqueFilename()', () => {
 
     it('generates a random file path', () => {
@@ -2094,43 +1782,6 @@ describe('stringify()', () => {
     });
 });
 
-describe('shallow()', () => {
-
-    it('shallow copies an object', () => {
-
-        const obj = {
-            a: 5,
-            b: {
-                c: 6
-            }
-        };
-
-        const shallow = Hoek.shallow(obj);
-        expect(shallow).to.not.shallow.equal(obj);
-        expect(shallow).to.equal(obj);
-        expect(shallow.b).to.equal(obj.b);
-    });
-
-    it('copies properties from a function', () => {
-
-        const fn = function () { };
-        fn.a = 5;
-        fn.b = { c: 6 };
-
-        const shallow = Hoek.shallow(fn);
-        expect(shallow).to.be.an.object();
-        expect(shallow).to.not.shallow.equal(fn);
-        expect(Object.entries(shallow)).to.equal(Object.entries(fn));
-        expect(shallow.b).to.equal(fn.b);
-    });
-
-    it('returns empty object for null and undefined', () => {
-
-        expect(Hoek.shallow(null)).to.equal({});
-        expect(Hoek.shallow(undefined)).to.equal({});
-    });
-});
-
 describe('block()', () => {
 
     it('executes ignore function', async () => {