The rule would catch the following cases:

.startsWith instead of:

• foo.indexOf('bar') === 0
• foo[0] === 'b'
• foo.charAt(0) === 'b' (and foo.charAt())
• foo.slice(0, 2) === 'bar' (and .substring & .substr)
• /^bar/.test(foo) (and .match())

.endsWith instead of:

• .lastIndexOf
• foo[foo.length - 1] === 'r'
• foo.charAt(foo.length - 1) === 'b'
• foo.slice(0, -3) === 'bar' (and .substring & .substr)
• /bar$/.test(foo) (and .match())

The regex case is especially useful as I've seen a lot of regexes used in this scenario.