Added assert package and added basic asserts

Author: halvardssm

assert/README.md

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+# @stdext/assert
+
+The assert package, contains validators and assertions
+
+```ts
+import { assertIsString, isString } from "@stdext/assert";
+
+if (isString(someVar)) {
+  // Returns true if a value is a string
+  // someVar will typewise be a string from now on
+}
+
+assertIsString(someVar); // Throws if the value is not a string
+// someVar will typewise be a string from now on
+```

assert/deno.json

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+{
+  "version": "0.0.1",
+  "name": "@stdext/assert",
+  "exports": {
+    ".": "./mod.ts",
+    "./is_number": "./is_number.ts",
+    "./is_record": "./is_record.ts",
+    "./is_string": "./is_string.ts"
+  }
+}

assert/is_number.test.ts

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+import { assert, assertFalse, AssertionError, assertThrows } from "@std/assert";
+import { assertIsNumber, isNumber } from "./is_number.ts";
+
+const VALID = [
+  0,
+  1,
+  1.123,
+  1_123_12_3,
+  -1,
+  -1_1234,
+  -1.123,
+  NaN,
+];
+
+const INVALID = [
+  "",
+  "asdf",
+  undefined,
+  null,
+  {},
+  [],
+  [""],
+  new Number(),
+];
+
+Deno.test("isNumber > can detect numbers", () => {
+  for (const v of VALID) {
+    assert(isNumber(v), `Value of '${v}' is not valid`);
+  }
+  for (const v of INVALID) {
+    assertFalse(isNumber(v), `Value of '${v}' is not invalid`);
+  }
+});
+
+Deno.test("assertIsNumber > can detect numbers", () => {
+  for (const v of VALID) {
+    assertIsNumber(v);
+  }
+  for (const v of INVALID) {
+    assertThrows(
+      () => assertIsNumber(v),
+      AssertionError,
+      undefined,
+      `Value of '${v}' did not throw`,
+    );
+  }
+});

assert/is_number.ts

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+import { AssertionError } from "@std/assert";
+
+/**
+ * Checks if a value is a number
+ */
+export function isNumber(value: unknown): value is number {
+  return typeof value === "number";
+}
+
+/**
+ * Asserts that a value is a number
+ */
+export function assertIsNumber(value: unknown): asserts value is number {
+  if (!isNumber(value)) {
+    throw new AssertionError(`Value is not a number, was '${value}'`);
+  }
+}

assert/is_numeric.test.ts

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+import { assert, assertFalse, AssertionError, assertThrows } from "@std/assert";
+import { assertIsNumeric, isNumeric } from "./is_numeric.ts";
+
+const VALID = [
+  0,
+  1,
+  1.123,
+  1_123_12_3,
+  -1,
+  -1_1234,
+  -1.123,
+];
+
+const INVALID = [
+  NaN,
+  "",
+  "asdf",
+  undefined,
+  null,
+  {},
+  [],
+  [""],
+  new Number(),
+];
+
+Deno.test("isNumeric > can detect numerics", () => {
+  for (const v of VALID) {
+    assert(isNumeric(v), `Value of '${v}' is not valid`);
+  }
+  for (const v of INVALID) {
+    assertFalse(isNumeric(v), `Value of '${v}' is not invalid`);
+  }
+});
+
+Deno.test("assertIsNumeric > can detect numerics", () => {
+  for (const v of VALID) {
+    assertIsNumeric(v);
+  }
+  for (const v of INVALID) {
+    assertThrows(
+      () => assertIsNumeric(v),
+      AssertionError,
+      undefined,
+      `Value of '${v}' did not throw`,
+    );
+  }
+});

assert/is_numeric.ts

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+import { AssertionError } from "@std/assert";
+import { isNumber } from "./is_number.ts";
+
+/**
+ * Checks if a value is a number and not NaN
+ */
+export function isNumeric(value: unknown): value is number {
+  return isNumber(value) && !Number.isNaN(value);
+}
+
+/**
+ * Asserts that a value is a number and not NaN
+ */
+export function assertIsNumeric(value: unknown): asserts value is number {
+  if (!isNumeric(value)) {
+    throw new AssertionError(`Value is not a numeric, was '${value}'`);
+  }
+}

assert/is_record.test.ts

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+import { assert, assertFalse, AssertionError, assertThrows } from "@std/assert";
+import { assertIsRecord, isRecord } from "./is_record.ts";
+
+const VALID = [
+  {},
+  { a: 1 },
+  { 1: "a" },
+];
+
+const INVALID = [
+  { [Symbol.dispose]: "" },
+  "",
+  1,
+  undefined,
+  null,
+  [],
+  [""],
+  new Map(),
+];
+
+Deno.test("isRecord > can detect records", () => {
+  for (const v of VALID) {
+    assert(isRecord(v), `Value of '${v}' is not valid`);
+  }
+  for (const v of INVALID) {
+    assertFalse(isRecord(v), `Value of '${v}' is not invalid`);
+  }
+});
+
+Deno.test("assertIsRecord > can detect records", () => {
+  for (const v of VALID) {
+    assertIsRecord(v);
+  }
+  for (const v of INVALID) {
+    assertThrows(
+      () => assertIsRecord(v),
+      AssertionError,
+      undefined,
+      `Value of '${v}' did not throw`,
+    );
+  }
+});

assert/is_record.ts

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+import { AssertionError } from "@std/assert";
+import { objectToStringEquals } from "./utils.ts";
+
+/**
+ * Checks if a value is a Record<string, unknown>
+ */
+export function isRecord(value: unknown): value is Record<string, unknown> {
+  if (!objectToStringEquals("Object", value)) {
+    return false;
+  }
+
+  if (typeof value !== "object") {
+    return false;
+  }
+
+  if (Array.isArray(value)) {
+    return false;
+  }
+
+  if (Object.getOwnPropertySymbols(value).length > 0) {
+    return false;
+  }
+
+  return true;
+}
+
+/**
+ * Asserts that a value is a record
+ */
+export function assertIsRecord(
+  value: unknown,
+): asserts value is Record<string, unknown> {
+  if (!isRecord(value)) {
+    throw new AssertionError(`Value is not a Record, was '${value}'`);
+  }
+}

assert/is_string.test.ts

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+import { assert, assertFalse, AssertionError, assertThrows } from "@std/assert";
+import { assertIsString, isString } from "./is_string.ts";
+
+const VALID = [
+  "",
+  "asdf",
+];
+
+const INVALID = [
+  1,
+  undefined,
+  null,
+  {},
+  [],
+  [""],
+  new String(),
+];
+
+Deno.test("isString > can detect strings", () => {
+  for (const v of VALID) {
+    assert(isString(v), `Value of '${v}' is not valid`);
+  }
+  for (const v of INVALID) {
+    assertFalse(isString(v), `Value of '${v}' is not invalid`);
+  }
+});
+
+Deno.test("assertIsString > can detect strings", () => {
+  for (const v of VALID) {
+    assertIsString(v);
+  }
+  for (const v of INVALID) {
+    assertThrows(
+      () => assertIsString(v),
+      AssertionError,
+      undefined,
+      `Value of '${v}' did not throw`,
+    );
+  }
+});

assert/is_string.ts

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+import { AssertionError } from "@std/assert";
+
+/**
+ * Checks if a value is a string
+ */
+export function isString(value: unknown): value is string {
+  return typeof value === "string";
+}
+
+/**
+ * Asserts that a value is a string
+ */
+export function assertIsString(value: unknown): asserts value is string {
+  if (!isString(value)) {
+    throw new AssertionError(`Value is not a string, was '${value}'`);
+  }
+}