Add {map,set}.clear.

Author: mbostock

README.md

@@ -247,7 +247,7 @@ Like [ES6 Maps](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Referenc
 * Keys are coerced to strings.
 * [map.set](#map_set) returns the new value, not the map itself.
 * [map.each](#map_each), not [map.forEach](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/forEach). (Also, no *thisArg*.)
-* [map.remove](#map_remove), not [map.delete](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/delete); also, no [map.clear](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/clear).
+* [map.remove](#map_remove), not [map.delete](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/delete).
 * [map.entries](#map_entries) returns an array of {key, value} objects, not an iterator of [key, value].
 * [map.size](#map_size) is a method, not a [property](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/size); also, there’s [map.empty](#map_empty).
 
@@ -280,6 +280,10 @@ Sets the *value* for the specified *key* string; returns the new *value*. If the
 
 If the map has an entry for the specified *key* string, removes the entry and returns true. Otherwise, this method does nothing and returns false.
 
+<a name="map_clear" href="#map_clear">#</a> <i>map</i>.<b>clear</b>()
+
+Removes all entries from this map.
+
 <a name="map_keys" href="#map_keys">#</a> <i>map</i>.<b>keys</b>()
 
 Returns an array of string keys for every entry in this map. The order of the returned keys is arbitrary.
@@ -311,7 +315,7 @@ Like [ES6 Sets](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Referenc
 * Values are coerced to strings.
 * [set.add](#set_add) returns the new value, not the set itself.
 * [set.each](#set_each), not [set.forEach](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/forEach). (Also, no *thisArg*.)
-* [set.remove](#set_remove), not [set.delete](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/delete); also, no [set.clear](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/clear).
+* [set.remove](#set_remove), not [set.delete](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/delete).
 * [set.size](#set_size) is a method, not a [property](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Set/size); also, there’s [set.empty](#set_empty).
 
 <a name="set" href="#set">#</a> <b>set</b>([<i>array</i>])
@@ -330,6 +334,10 @@ Adds the specified *value* string to this set. Returns *value*.
 
 If the set contains the specified *value* string, removes it and returns true. Otherwise, this method does nothing and returns false.
 
+<a name="set_clear" href="#set_clear">#</a> <i>set</i>.<b>clear</b>()
+
+Removes all values from this set.
+
 <a name="set_values" href="#set_values">#</a> <i>set</i>.<b>values</b>()
 
 Returns an array of the string values in this set. The order of the returned values is arbitrary. Can be used as a convenient way of computing the unique values for a set of strings. For example:

package.json

@@ -1,6 +1,6 @@
 {
   "name": "d3-arrays",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "Array manipulation, ordering, searching, summarizing, etc.",
   "keywords": [
     "d3",

src/map.js

@@ -16,6 +16,9 @@ Map.prototype = map.prototype = {
     var property = prefix + key;
     return property in this && delete this[property];
   },
+  clear: function() {
+    for (var property in this) if (property[0] === prefix) delete this[property];
+  },
   keys: function() {
     var keys = [];
     for (var property in this) if (property[0] === prefix) keys.push(property.slice(1));

src/set.js

@@ -12,6 +12,7 @@ Set.prototype = set.prototype = {
     return value;
   },
   remove: proto.remove,
+  clear: proto.clear,
   values: proto.keys,
   size: proto.size,
   empty: proto.empty,

test/map-test.js

@@ -91,6 +91,17 @@ tape("map.size() returns the number of distinct keys", function(test) {
   test.end();
 });
 
+tape("map.clear() removes all entries", function(test) {
+  var m = arrays.map();
+  m.set("foo", 1);
+  m.set("bar", 2);
+  m.set("foo", 3);
+  m.clear();
+  test.equal(m.size(), 0);
+  test.deepEqual(m.entries(), []);
+  test.end();
+});
+
 tape("map.empty() returns true only if the map is empty", function(test) {
   var m = arrays.map();
   test.equal(m.empty(), true);

test/set-test.js

@@ -51,6 +51,17 @@ tape("set.size() returns the number of distinct values", function(test) {
   test.end();
 });
 
+tape("set.clear() removes all values", function(test) {
+  var s = arrays.set();
+  s.add("foo");
+  s.add("bar");
+  s.add("foo");
+  s.clear();
+  test.equal(s.size(), 0);
+  test.deepEqual(s.values(), []);
+  test.end();
+});
+
 tape("set.empty() returns true only if the set is empty", function(test) {
   var s = arrays.set();
   test.equal(s.empty(), true);