51 lines
982 B
TypeScript
51 lines
982 B
TypeScript
/**
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* Predicate that always returns true
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*/
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export const always = (...args: any[]) => true;
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/**
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* Predicate that always returns false
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*/
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export const never = (...args: any[]) => false;
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/**
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* Negate a predicate
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*/
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export function not<A extends any[]>(
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predicate: (...args: A) => boolean,
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): (...args: A) => boolean {
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return (...args) => !predicate(...args);
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}
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/**
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* Apply a boolean "and" to merge predicates
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*/
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export function and<A extends any[]>(
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...predicates: ((...args: A) => boolean)[]
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): (...args: A) => boolean {
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return (...args) => {
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for (let p of predicates) {
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if (!p(...args)) {
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return false;
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}
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}
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return true;
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};
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}
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/**
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* Apply a boolean "or" to merge predicates
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*/
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export function or<A extends any[]>(
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...predicates: ((...args: A) => boolean)[]
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): (...args: A) => boolean {
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return (...args) => {
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for (let p of predicates) {
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if (p(...args)) {
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return true;
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}
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}
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return false;
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};
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}
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