add encode base32 func

.gitignore

@@ -0,0 +1 @@
+node_modules/

base32.js

@@ -0,0 +1,77 @@
+const encodeTable = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567'.split('')
+const decodeTable = {}
+for (const idx in encodeTable) {
+  decodeTable[encodeTable[idx]] = idx
+}
+
+const base32 = {}
+module.exports = base32
+
+base32.encode = (b) => {
+  if (!(b instanceof Buffer)) return ''
+  if (b.length === 0) return ''
+
+  let str = ''
+  const len = b.length
+  let v1, v2, v3, v4, v5
+
+  const count = parseInt(len / 5) * 5
+  let i = 0
+  while (i < count) {
+    v1 = b[i++]
+    v2 = b[i++]
+    v3 = b[i++]
+    v4 = b[i++]
+    v5 = b[i++]
+    str += encodeTable[v1 >>> 3] +
+      encodeTable[(v1 << 2 | v2 >>> 6) & 31] +
+      encodeTable[(v2 >>> 1) & 31] +
+      encodeTable[(v2 << 4 | v3 >>> 4) & 31] +
+      encodeTable[(v3 << 1 | v4 >>> 7) & 31] +
+      encodeTable[(v4 >>> 2) & 31] +
+      encodeTable[(v4 << 3 | v5 >>> 5) & 31] +
+      encodeTable[v5 & 31]
+  }
+
+  const remain = len - count
+  switch (remain) {
+    case 1:
+      v1 = b[i]
+      str += encodeTable[v1 >>> 3] +
+        encodeTable[(v1 << 2) & 31] + '======'
+      break
+    case 2:
+      v1 = b[i++]
+      v2 = b[i]
+      str += encodeTable[v1 >>> 3] +
+        encodeTable[(v1 << 2 | v2 >>> 6) & 31] +
+        encodeTable[(v2 >>> 1) & 31] +
+        encodeTable[(v2 << 4) & 31] + '===='
+      break
+    case 3:
+      v1 = b[i++]
+      v2 = b[i++]
+      v3 = b[i]
+      str += encodeTable[v1 >>> 3] +
+        encodeTable[(v1 << 2 | v2 >>> 6) & 31] +
+        encodeTable[(v2 >>> 1) & 31] +
+        encodeTable[(v2 << 4 | v3 >>> 4) & 31] +
+        encodeTable[(v3 << 1) & 31] + '==='
+      break
+    case 4:
+      v1 = b[i++]
+      v2 = b[i++]
+      v3 = b[i++]
+      v4 = b[i]
+      str += encodeTable[v1 >>> 3] +
+        encodeTable[(v1 << 2 | v2 >>> 6) & 31] +
+        encodeTable[(v2 >>> 1) & 31] +
+        encodeTable[(v2 << 4 | v3 >>> 4) & 31] +
+        encodeTable[(v3 << 1 | v4 >>> 7) & 31] +
+        encodeTable[(v4 >>> 2) & 31] +
+        encodeTable[(v4 << 3) & 31] + '='
+      break
+  }
+
+  return str
+}

package.json

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+{
+  "name": "node-base32",
+  "version": "1.0.0",
+  "description": "",
+  "main": "index.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC",
+  "devDependencies": {
+    "standard": "^12.0.1"
+  }
+}