There’re a lot of examples of masking names with RegExp but I couldn’t find my case.

I want to mask companies names according to the following examples:

ST --> S*
STE --> S*E
STEP --> S**P
Apple --> A***e
Mozilla --> Mo****la
Mozilla Firefox --> Moz**** ****fox
LTD Best Company --> LTD **** ****any
Telecommunications --> Tel************ons
No Matter How Long --> No ****** *** *ong
GRAS Company Name --> GRA* ******* *ame 

Any ideas? Please, help.

>Solution :

You can use a loop

function mask(string) {
  const show = string.length > 7 ? 3 : string.length > 5 ? 2 : 1

  const result = []

  for (let i = 0; i < string.length; i += 1) {
    const char = string[i]
    if (i < show || i > string.length - show - 1 || char === ' ') {
      result.push(char)
    } else {
      result.push('*')
    }
  }

  return result.join('')
}

const strings = [
  'ST', // --> S*
  'STE', // --> S*E
  'STEP', // --> S**P
  'Apple', // --> A***e
  'Mozilla', // --> Mo****la
  'Mozilla Firefox', // --> Moz**** ****fox
  'LTD Best Company', // --> LTD **** ****any
  'Telecommunications', // --> Tel************ons
  'No Matter How Long', // --> No ****** *** *ong
  'GRAS Company Name', // --> GRA* ******* *ame 
]

for (const string of strings) {
  console.log(string, '-->', mask(string))
}

function mask(string) {
  const show = string.length > 7 ? 3 : string.length > 5 ? 2 : 1

  const result = []

  for (let i = 0; i < string.length; i += 1) {
    const char = string[i]
    if (i < show || i > string.length - show - 1 || char === ' ') {
      result.push(char)
    } else {
      result.push('*')
    }
  }

  return result.join('')
}