Test if string is in Upper Camel Case format with only alphabetic characters

Question

I try to test if the following rules apply on a string:

Must start with uppercase letter.
Next characters can be either in uppercase or lowercase format.
Only the following characters are allowed: A-z

For instance, a string can be either String or CamelCaseString, but neither string nor Camel-Case-String nor String125. Numerics and special characters must not exist.

I found this answer in a previous post.

const isUpperCamelCase = (str) => {
  return /\b[A-Z][a-z]*([A-Z][a-z]*)*\b/.test(str)
}

I have the following test suit that tries to test the above function. Unfortunately, not all tests pass:

test('isUpperCamelCase', () => {
    expect(isUpperCamelCase('Button')).toBeTruthy()
    expect(isUpperCamelCase('GreenButton')).toBeTruthy()
    expect(isUpperCamelCase('GreenLargeButton')).toBeTruthy()
    expect(isUpperCamelCase('B')).toBeTruthy()

    expect(isUpperCamelCase('button')).toBeFalsy()
    expect(isUpperCamelCase('buttonCamel')).toBeFalsy()
    expect(isUpperCamelCase('Green-Button')).toBeFalsy() // => fail!
    expect(isUpperCamelCase('Button125')).toBeFalsy()
    expect(isUpperCamelCase('Green_Button')).toBeFalsy()
    expect(helpers.isUpperCamelCase('Green+Button')).toBeFalsy() // => fail!
    expect(helpers.isUpperCamelCase('green+Button')).toBeFalsy() // => fail!
})

If I include special characters such as (,)+- in my string the function evaluates to true when it should evaluate to false. this happens because there exists a match between the special chars, but this is not the behavior that I want. How can I solve this problem?

Note: Please add detail explanation in your answer. Thanks! :)

@anubhava thanks that seem to work! Please post an answer if you would like! :) — georgegkas, Mar 02 '18 at 21:12
Note that I would not consider AB camelcase, but maybe it matches your definition. — Peter B, Mar 02 '18 at 21:14
@HunterMcMillen that's a valid camel case string. Consider "pin", as in "personal identification number". You would typically camel case this as "PIN", not "Pin". — user229044, Mar 02 '18 at 21:14

score 6 · Accepted Answer · answered Mar 02 '18 at 21:12

6

You regex needs anchors for matching beginning and ending of the string, not \b. So do:

/^[A-Z][A-Za-z]*$/

answered Mar 02 '18 at 21:12

trincot

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Test if string is in Upper Camel Case format with only alphabetic characters

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