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Task/Prime-decomposition/JavaScript/prime-decomposition-3.js

@@ -0,0 +1,14 @@
+function factors(n) {
+  if (!n || n < 2)
+    return [];
+
+  var f = [];
+  for (var i = 2; i <= n; i++){
+    while (n % i === 0){
+      f.push(i);
+      n /= i;
+    }
+  }
+
+  return f;
+};

Task/Prime-decomposition/JavaScript/prime-decomposition-4.js

@@ -0,0 +1,48 @@
+/// <reference path="PrimeFactors.js" />
+
+describe("Prime Factors", function() {
+  it("Given nothing, empty is returned", function() {
+    expect(factors()).toEqual([]);
+  });
+
+  it("Given 1, empty is returned", function() {
+    expect(factors(1)).toEqual([]);
+  });
+
+  it("Given 2, 2 is returned", function() {
+    expect(factors(2)).toEqual([2]);
+  });
+
+  it("Given 3, 3 is returned", function() {
+    expect(factors(3)).toEqual([3]);
+  });
+
+  it("Given 4, 2 and 2 is returned", function() {
+    expect(factors(4)).toEqual([2, 2]);
+  });
+
+  it("Given 5, 5 is returned", function() {
+    expect(factors(5)).toEqual([5]);
+  });
+
+  it("Given 6, 2 and 3 is returned", function() {
+    expect(factors(6)).toEqual([2, 3]);
+  });
+
+  it("Given 7, 7 is returned", function() {
+    expect(factors(7)).toEqual([7]);
+  });
+
+  it("Given 8; 2, 2, and 2 is returned", function() {
+    expect(factors(8)).toEqual([2, 2, 2]);
+  });
+
+  it("Given a large number, many primes factors are returned", function() {
+    expect(factors(2*2*2*3*3*7*11*17))
+      .toEqual([2, 2, 2, 3, 3, 7, 11, 17]);
+  });
+
+  it("Given a large prime number, that number is returned", function() {
+    expect(factors(997)).toEqual([997]);
+  });
+});