startsWith(): check the start of text

In a few sentences

In brief

The method is sensitive to upper and lower case letters.

Useful to know

startsWith() checks if the string starts with a given sequence and returns a Boolean value. For example, "BG-104".startsWith("BG-") is true, and verification for "bg-" is false. [1]

For an internal product code, this may be exactly the desired behavior. If the input must be insensitive to letter case, define an explicit normalization rule. Do not use a text prefix as a background check for a secure URL or allowed file path: the structure and origin of such values require corresponding parsing and validation.

Sources

For further detail and to check the information:

[1] MDN — String.startsWith ↗