feat: Add has‑symbols (#44917)

types/has-symbols/has-symbols-tests.ts

@@ -0,0 +1,5 @@
+import hasNativeSymbols = require('has-symbols');
+import hasSymbolSham = require('has-symbols/shams');
+
+hasNativeSymbols(); // $ExpectType boolean
+hasSymbolSham(); // $ExpectType boolean

types/has-symbols/index.d.ts

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+// Type definitions for has-symbols 1.0
+// Project: https://github.com/ljharb/has-symbols#readme
+// Definitions by: Jordan Harband <https://github.com/ljharb>
+//                 ExE Boss <https://github.com/ExE-Boss>
+// Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
+
+/**
+ * Returns `true` only if the environment has native `Symbol` support.
+ *
+ * Not polyfillable, not forgeable.
+ */
+declare function hasNativeSymbols(): boolean;
+export = hasNativeSymbols;

types/has-symbols/shams.d.ts

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+/**
+ * Returns `true` if the environment has a `Symbol` sham
+ * that mostly follows the spec.
+ */
+declare function hasSymbolSham(): boolean;
+export = hasSymbolSham;

types/has-symbols/tsconfig.json

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+{
+    "compilerOptions": {
+        "module": "commonjs",
+        "lib": ["ES2015"],
+        "noImplicitAny": true,
+        "noImplicitThis": true,
+        "strictFunctionTypes": true,
+        "strictNullChecks": true,
+        "baseUrl": "../",
+        "typeRoots": ["../"],
+        "types": [],
+        "noEmit": true,
+        "forceConsistentCasingInFileNames": true
+    },
+    "files": [
+        "has-symbols-tests.ts",
+        "index.d.ts"
+    ]
+}

types/has-symbols/tslint.json

@@ -0,0 +1 @@
+{ "extends": "dtslint/dt.json" }