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 22.09 kB 21.13 kB -0.96 kB (-4.35 %)
bootstrap.min.js 15.4 kB 14.46 kB -0.94 kB (-3.86 %)