Both slice(start, end) and substring(start, end) methods extract a portion of a string. The start parameter specifies the zero-based index at which to begin extraction, and the end parameter specifies the index before which to end extraction. For the string 'Salesforce', the substring 'Sales' begins at index 0 and ends at index 4. Therefore, specifying a start of 0 and an end of 5 will extract characters from index 0 up to, but not including, index 5, resulting in 'Sales'.

1. ECMA International. (2023). ECMAScript® 2023 Language Specification (14th ed.

ECMA-262). Section 22.1.3.26

String.prototype.slice(start

end)

and Section 22.1.3.30

String.prototype.substring(start

end). The specification details that both methods extract characters from the start index up to the end index

where the character at the end index is not included.

2. Massachusetts Institute of Technology. (2013). 6.170 Software Studio

Lecture 2: JavaScript. MIT OpenCourseWare. The lecture notes cover core JavaScript features

including string manipulation methods like slice and substring

explaining their usage for extracting parts of a string based on indices. (ocw.mit.edu)

3. Haverbeke

M. (2018). Eloquent JavaScript (3rd ed.). No Starch Press. Chapter 4

"Data Structures: Objects and Arrays

" section on "Strings and their properties." This text

often used in university curricula

explains that slice and substring are similar in taking start and end indices to create a new string.