Javascript Replace String Dot Notation with Square Brackets

Question

I'm trying to figure out how to replace a string in dot notation with square brackets:

emergency.1.phone.2

Should convert to:

emergency[1][phone][2]

I'm trying to make it dynamic so it will convert the string regardless of how many dots there are.

Answer 1

You could do this by using the string .replace method with a regex with a special replacement function.

The regex is /\.(.+?)(?=\.|$)/g, which looks for:

• a literal ., followed by
• anything, until:
• another literal . or the end of the string

Then, you can specify a function which takes the captured string and puts it in brackets, and use that as the replacer.

Example:

const dots = "emergency.1.phone.2"

// Should convert to:
// emergency[1][phone][2]

console.log(dots.replace(/\.(.+?)(?=\.|$)/g, (m, s) => `[${s}]`))

Answer 2

const originalString = 'emergency.1.phone.2'
const desiredString = originalString
  .split('.')
  .reduce((fullPath, arg) => fullPath + `['${arg}']`)

console.log(desiredString)

// logs: emergency['1']['phone']['2']

Answer 3

An alternative is using the function reduce.

let str = "emergency.1.phone.2",
    arr = str.split('.'),
    result = arr.reduce((a, s, i) => i === 0 ? s : a + `[${s}]`);
    
console.log(result);

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