An enum-like type for representing & using bit flags
Note: I don't particularly recommend using this package! Bit flags are great,
and can be created and used quite simply in TypeScript (demonstrated in
fantastically concise fashion in this SO
answer). This package abstracts
away the bitwise operations, but is not without performance cost. As long as
you're fine with seeing | and &, use native bit flag enums!
Also note: JS coerces numbers to 32 bits before performing any bitwise
operations, so the maximum number of flags that can be represented by a bit
flag type is 32!
const PermissionsFlag = bitFlag('Read', 'Write', 'Execute');
const userPermissions = PermissionsFlag.union(PermissionsFlag.Read, PermissionsFlag.Write);
const canRead = userPermissions.hasFlag(PermissionsFlag.Read); // true
const canExecute = userPermissions.hasFlag(PermissionsFlag.Execute); // falseAn alternative syntax that creates an 'enum' with object-valued (instead of
Number-valued, as in bitFlag) members. While this has higher one-time
allocation cost, there are more utilities for working with the values
themselves on the enum member instances.
const PermissionsFlag = createBitFlagsEnum(['Read', 'Write', 'Execute'] as const);
{ // offers 'or' syntax on the enum value itself
const userPermissions = PermissionsFlag.Read
.or(PermissionsFlag.Write)
.or(PermissionsFlag.Execute);
const canRead = userPermissions.hasFlag(PermissionsFlag.Read); // true
const canExecute = userPermissions.hasFlag(PermissionsFlag.Execute); // true
}
{ // static `union` works in the same fashion as bitFlag
const userPermissions = PermissionsFlag.union([PermissionsFlag.Read, PermissionsFlag.Write]);
const canRead = userPermissions.hasFlag(PermissionsFlag.Read); // true
const canExecute = userPermissions.hasFlag(PermissionsFlag.Execute); // false
}