初始化环境文件

node_modules/@aws-crypto/sha256-browser/README.md

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+# @aws-crypto/sha256-browser
+
+SHA256 wrapper for browsers that prefers `window.crypto.subtle` but will
+fall back to a pure JS implementation in @aws-crypto/sha256-js
+to provide a consistent interface for SHA256.
+
+## Usage
+
+- To hash "some data"
+```
+import {Sha256} from '@aws-crypto/sha256-browser'
+
+const hash = new Sha256();
+hash.update('some data');
+const result = await hash.digest();
+
+```
+
+- To hmac "some data" with "a key"
+```
+import {Sha256} from '@aws-crypto/sha256-browser'
+
+const hash = new Sha256('a key');
+hash.update('some data');
+const result = await hash.digest();
+
+```
+
+## Test
+
+`npm test`