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constant

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This function uses the rulr.isConstant guard to check the input matches a constant as shown in the example below. It should only throw rulr.InvalidConstantError. You may want to consider using rulr.literal instead.

import * as rulr from 'rulr'

const exampleSymbol = Symbol()
const constrainToExample = rulr.object({
	required: {
		example: rulr.constant(exampleSymbol, true),
	},
})

type Example = rulr.Static<typeof constrainToExample>
// {
//   example: rulr.Constraint<typeof exampleSymbol, true>
// }

// Valid
const example1: Example = constrainToExample({
	example: true,
})

// Invalid
const example2: Example = constrainToExample({
	example: false,
})