diff --git a/dist/js/index.d.ts b/dist/js/index.d.ts
index d49b4aa..c4464d5 100644
--- a/dist/js/index.d.ts
+++ b/dist/js/index.d.ts
@@ -1,7 +1,7 @@
 import * as array from "./shared/array";
+import * as assertion from "./shared/assertion";
 import * as cls from "./shared/class";
 import * as clone from "./shared/clone";
-import * as compare from "./shared/compare";
 import * as constants from "./shared/constants";
 import * as hash from "./shared/hash";
 import * as math from "./shared/math";
@@ -26,7 +26,7 @@ export declare const sharedUtils: {
     tree: typeof tree;
     url: typeof url;
     uuid: typeof uuid;
-    compare: typeof compare;
+    assertion: typeof assertion;
 };
 export declare const Utils: {
     array: typeof array;
@@ -42,7 +42,7 @@ export declare const Utils: {
     tree: typeof tree;
     url: typeof url;
     uuid: typeof uuid;
-    compare: typeof compare;
+    assertion: typeof assertion;
 };
 declare const _default: {
     array: typeof array;
@@ -58,6 +58,6 @@ declare const _default: {
     tree: typeof tree;
     url: typeof url;
     uuid: typeof uuid;
-    compare: typeof compare;
+    assertion: typeof assertion;
 };
 export default _default;
diff --git a/dist/js/index.js b/dist/js/index.js
index b4e7084..b192e2c 100644
--- a/dist/js/index.js
+++ b/dist/js/index.js
@@ -43,9 +43,9 @@ var __importStar =
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.Utils = exports.sharedUtils = void 0;
 const array = __importStar(require("./shared/array"));
+const assertion = __importStar(require("./shared/assertion"));
 const cls = __importStar(require("./shared/class"));
 const clone = __importStar(require("./shared/clone"));
-const compare = __importStar(require("./shared/compare"));
 const constants = __importStar(require("./shared/constants"));
 const hash = __importStar(require("./shared/hash"));
 const math = __importStar(require("./shared/math"));
@@ -70,7 +70,7 @@ exports.sharedUtils = {
     tree,
     url,
     uuid,
-    compare,
+    assertion,
 };
 exports.Utils = exports.sharedUtils;
 exports.default = { ...exports.Utils };
diff --git a/dist/js/index_browser.d.ts b/dist/js/index_browser.d.ts
index 62de13b..0344e40 100644
--- a/dist/js/index_browser.d.ts
+++ b/dist/js/index_browser.d.ts
@@ -17,7 +17,7 @@ export declare const Utils: {
     tree: typeof import("./shared/tree");
     url: typeof import("./shared/url");
     uuid: typeof import("./shared/uuid");
-    compare: typeof import("./shared/compare");
+    assertion: typeof import("./shared/assertion");
 };
 declare const _default: {
     codemirror: typeof codemirror;
@@ -34,6 +34,6 @@ declare const _default: {
     tree: typeof import("./shared/tree");
     url: typeof import("./shared/url");
     uuid: typeof import("./shared/uuid");
-    compare: typeof import("./shared/compare");
+    assertion: typeof import("./shared/assertion");
 };
 export default _default;
diff --git a/dist/js/index_server.d.ts b/dist/js/index_server.d.ts
index f6efc60..57d8632 100644
--- a/dist/js/index_server.d.ts
+++ b/dist/js/index_server.d.ts
@@ -17,7 +17,7 @@ export declare const Utils: {
     tree: typeof import("./shared/tree");
     url: typeof import("./shared/url");
     uuid: typeof import("./shared/uuid");
-    compare: typeof import("./shared/compare");
+    assertion: typeof import("./shared/assertion");
 };
 declare const _default: {
     file: typeof file;
@@ -34,6 +34,6 @@ declare const _default: {
     tree: typeof import("./shared/tree");
     url: typeof import("./shared/url");
     uuid: typeof import("./shared/uuid");
-    compare: typeof import("./shared/compare");
+    assertion: typeof import("./shared/assertion");
 };
 export default _default;
diff --git a/dist/js/shared/assertion.d.ts b/dist/js/shared/assertion.d.ts
new file mode 100644
index 0000000..bae68b1
--- /dev/null
+++ b/dist/js/shared/assertion.d.ts
@@ -0,0 +1,6 @@
+export declare function assertShallowDeepAlmostEqual(
+    expect?: object | boolean | number | null | string | Date,
+    actual?: object | boolean | number | null | string | Date,
+    path?: string,
+    threshold?: number,
+): boolean;
diff --git a/dist/js/shared/assertion.js b/dist/js/shared/assertion.js
new file mode 100644
index 0000000..e9885a9
--- /dev/null
+++ b/dist/js/shared/assertion.js
@@ -0,0 +1,70 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.assertShallowDeepAlmostEqual = void 0;
+function assertShallowDeepAlmostEqual(expect, actual, path = "", threshold = 0.01) {
+    // null value
+    if (expect === null) {
+        if (!(actual === null)) {
+            throw new Error(`Expected to have null but got "${actual}" at path "${path}".`);
+        }
+        return true;
+    }
+    // undefined expected value
+    if (typeof expect === "undefined") {
+        if (typeof actual !== "undefined") {
+            throw new Error(`Expected to have undefined but got "${actual}" at path "${path}".`);
+        }
+        return true;
+    }
+    // scalar description
+    if (typeof expect === "boolean" || typeof expect === "string") {
+        if (expect !== actual) {
+            throw new Error(`Expected to have "${expect}" but got "${actual}" at path "${path}".`);
+        }
+        return true;
+    }
+    // numbers — here is some important 'almost equal' stuff
+    // TODO: configurable threshold
+    if (typeof expect === "number") {
+        if (typeof actual !== "number") {
+            throw new Error(`Expected to have number but got "${actual}" at path "${path}".`);
+        }
+        if (Math.abs(expect - actual) > threshold) {
+            throw new Error(
+                `Expected to have "${expect}+-${threshold}" but got "${actual}" at path "${path}".`,
+            );
+        }
+        return true;
+    }
+    // dates
+    if (expect instanceof Date) {
+        if (actual instanceof Date) {
+            if (expect.getTime() !== actual.getTime()) {
+                throw new Error(
+                    `Expected to have date "${expect.toISOString()}" but got "${actual.toISOString()}" at path "${path}".`,
+                );
+            }
+        } else {
+            throw new Error(
+                `Expected to have date "${expect.toISOString()}" but got "${actual}" at path "${path}".`,
+            );
+        }
+        return true;
+    }
+    if (actual === null) {
+        throw new Error(`Expected to have an array/object but got null at path "${path}".`);
+    }
+    // array/object description
+    // eslint-disable-next-line no-restricted-syntax, guard-for-in
+    for (const prop in expect) {
+        // @ts-ignore
+        if (typeof actual[prop] === "undefined" && typeof expect[prop] !== "undefined") {
+            throw new Error(`Expected "${prop}" field to be defined at path "${path}".`);
+        }
+        const newPath = path + (path === "/" ? "" : "/") + prop;
+        // @ts-ignore
+        shallowDeepAlmostEqual(expect[prop], actual[prop], newPath, threshold);
+    }
+    return true;
+}
+exports.assertShallowDeepAlmostEqual = assertShallowDeepAlmostEqual;