util

• URL
• [Doc] Query Strings
• [Doc] Utilities
• [Basic] Regex

Want to know more? Try this:

Array(range).fill(0)
  .map((_, i) => String.fromCharCode(i))
  .map(encodeURI)

Try to set the range to 255 first (doge.

A query string is the part of a URL referring to the table above. Node.js provides a module called querystring.

Converts a json object to a query string|
|.escape(str)|Inner method used by .stringify(). It is exported primarily to allow application code to provide a replacement percent-encoding implementation if necessary.|

So far, the Node.js built-in querystring does not support for the deep structure:

const qs = require('qs');
let arr = [1,2,3,4];
let str = qs.stringify({arr});
console.log(str); // arr%5B0%5D=1&arr%5B1%5D=2&arr%5B2%5D=3&arr%5B3%5D=4
console.log(decodeURI(str)); // 'arr[0]=1&arr[1]=2&arr[2]=3&arr[3]=4'
console.log(qs.parse(str)); // { arr: [ '1', '2', '3', '4' ] }

You can pass arr Array to the server vir https://your.host/api/?arr[0]=1&arr[1]=2&arr[2]=3&arr[3]=4.

In v4.0.0 or later, util.is*() is not recommended and deprecated. Maybe it is because that maintaining the library is thankless and there are so many popular libraries. The following is the list:

• util.debug(string)
• util.isArray(object)
• util.isBoolean(object)
• util.isBuffer(object)
• util.isDate(object)
• util.isError(object)
• util.isFunction(object)
• util.isNull(object)
• util.isNullOrUndefined(object)
• util.isNumber(object)
• util.isObject(object)
• util.isPrimitive(object)
• util.isRegExp(object)
• util.isString(object)
• util.isSymbol(object)
• util.isUndefined(object)
• util.log(string)
• util.print([…strings])
• util.puts([…strings])
• util._extend(target, source)

Most of them can be used as an interview to ask how to implement.

util.inherits

Collecting…

Awesome Node.js

const fs = require('fs');
const path = require('path');
  for (let item of fs.readdirSync(dir)) {
    let filepath = path.join(dir, item);
    try {
      let fd = fs.openSync(filepath, 'r');
      let flag = fs.fstatSync(fd).isDirectory();
      fs.close(fd); // TODO
      if (flag) {
        res.push(...traversal(filepath));
      } else {
        res.push(filepath);
      }
    } catch(err) {
      if (err.code === 'ENOENT' && // can not open link file
          !!fs.readlinkSync(filepath)) { // if it is a link file
        res.push(filepath);
      } else {
        console.error('err', err);
      }
    } 
  }
  return res.map((file) => path.basename(file));
}

Of course you can also use Oh my glob:

```javascript
const glob = require(“glob”);