setup tests with jest

__tests__/array.test.js

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+// @ts-nocheck
+const arrayEvery = Array.prototype.every;
+const arrayFilter = Array.prototype.filter;
+beforeAll(() => {
+  Array.prototype.every = undefined;
+  Array.prototype.filter = undefined;
+});
+afterAll(() => {
+  Array.prototype.every = arrayEvery;
+  Array.prototype.filter = arrayFilter;
+});
+describe("array tests", () => {
+  test("filter should work", () => {
+    require("../Array/filter");
+    const arr = [1, 2, 3];
+    const res = arr.filter((ele, i, arr) => ele === 1);
+    expect(res[0]).toBe(1);
+  });
+  test("every shoud work", () => {
+    require("../Array/every");
+    const arr = [1, 2, 3];
+    expect(
+      arr.every(function(ele, i, arr) {
+        return ele < 4;
+      })
+    ).toBe(true);
+  });
+});

jest.config.js

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+module.exports = {
+  testEnvironment: "jest-environment-node",
+  collectCoverage: true,
+  coverageReporters: ["lcov", "text"],
+  collectCoverageFrom: [
+    "Array/**/*.{js}",
+    "Date/**/*.{js}",
+    "Object/**/*.{js}"
+  ],
+  coverageThreshold: {
+    global: {
+      branches: 75,
+      functions: 75,
+      lines: 75,
+      statements: 75
+    }
+  }
+};