This allows the minifier to mangle the constants. It also allows the linter to find unused strings properly.
While at it, remove a few unused properties.
File Before After Diff
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bootstrap.bundle.min.js 23.61 kB 22.61 kB -1.00 kB (-4.23 %)
bootstrap.min.js 17.04 kB 16.08 kB -0.96 kB (-5.63 %)