modify buffer code

Author: wangding

02-global/02-base64.js

@@ -5,12 +5,15 @@ const log = console.log,
       pwd = process.argv[3];
 
 if(process.argv.length !== 4) {
-  console.error('命令行格式：cmd username password');
+  console.error('usage：cmd username password');
   process.exit(1);
 }
 
 log('user name: %s\npassword: %s', usr, pwd);
 
-const buf = Buffer.from(usr + ':' + pwd);
+// method A
+log('Base64:', btoa(usr + ':' + pwd));
 
+// method B
+const buf = Buffer.from(usr + ':' + pwd);
 log('Base64:', buf.toString('Base64'));

06-buffer/02-encode.js

@@ -1,12 +1,19 @@
 #!/usr/bin/env node
 
 if(process.argv.length !== 3) {
-  console.error('命令行格式：cmd base64_string');
+  console.error('usage：cmd base64_string');
   process.exit(1);
 }
 
+// method A
+const buf = atob(process.argv[2]);
+const info = buf.split(':');
+
+// method B
+/*
 const buf = Buffer.from(process.argv[2], 'base64');
 const info = buf.toString('utf8').split(':');
+*/
 
 if(info.length !== 2) {
   console.error('信息有误！');

06-buffer/03-decode.js

@@ -0,0 +1,42 @@
+#!/usr/bin/env node
+
+const dec2Hex = num => num.toString(16);
+
+function utf8Code(str) {
+  const code = encodeURI(str)
+                .replace(/%/g, ' ')
+                .trim();
+  return code == str ? utf16Code(str).slice(3) : code;
+}
+
+const utf8 = new TextEncoder();
+function utf8CodeV2(str) {
+  return Array.from(utf8.encode(str))
+    .map(dec2Hex)
+    .join(' ')
+    .toUpperCase();
+}
+
+function utf16Code(str) {
+  const code = dec2Hex(str.charCodeAt(0))
+                .toUpperCase()
+                .replace(/(\w{2})/g, '$1 ')
+                .trim();
+  return code.length == 2 ? '00 ' + code : code;
+}
+
+function getCodeInfo(c) {
+  return {
+    "char":   c,
+    "UTF-8":  utf8Code(c),
+    "UTF-16": utf16Code(c),
+  };
+}
+
+function main() {
+  const msg = 'hello, 王顶';
+  const codes = [...msg].map(getCodeInfo);
+  console.table(codes);
+}
+
+main();

06-buffer/07-show-utf-code.js

@@ -0,0 +1,34 @@
+#!/usr/bin/env node
+
+const dec2Hex = num => num.toString(16);
+
+String.prototype.toUTF8Code = function () {
+  const code = encodeURI(this[0])
+                .replace(/%/g, ' ')
+                .trim();
+  return (code == this[0]) ? this[0].toUTF16Code().slice(3) : code;
+}
+
+String.prototype.toUTF16Code = function() {
+  const code = dec2Hex(this.charCodeAt(0))
+          .toUpperCase()
+          .replace(/(\w{2})/g, '$1 ')
+          .trim();
+  return code.length == 2 ? '00 ' + code : code;
+}
+
+function getCodeInfo(c) {
+  return {
+    "char":   c,
+    "UTF-8":  c.toUTF8Code(),
+    "UTF-16": c.toUTF16Code(),
+  };
+}
+
+function main() {
+  const msg = 'hello, 王顶';
+  const codes = [...msg].map(getCodeInfo);
+  console.table(codes);
+}
+
+main();