76 lines
1.9 KiB
JavaScript
76 lines
1.9 KiB
JavaScript
import { Item_Unresolvable } from '@efforting.tech/errors';
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export class Abstract_Resolver {
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resolve(item, extra_info={}) {
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const result = this.resolve_handler(item);
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if (!result?.handler) {
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throw new Item_Unresolvable({ resolver: this, item });
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}
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// TO DOC: Spreading result into the resulting context means there are some reserved keys we need to be mindful of to avoid clobbering them
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return result.handler({ resolver: this, item, ...extra_info, ...result });
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}
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}
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export class Chained_Resolver extends Abstract_Resolver {
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constructor(chain_links) {
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super();
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Object.assign(this, { chain_links });
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}
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resolve_handler(item) {
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const { chain_links } = this;
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for (const link of chain_links) {
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const result = link.resolve_handler(item);
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if (result?.handler) {
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return result;
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}
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}
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}
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}
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export class Predicate_Resolver extends Abstract_Resolver {
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constructor(rules=[]) {
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// NOTE: Rules should be iterable as [predicate, handler] pairs
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super();
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Object.assign(this, { rules });
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}
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resolve_handler(item) {
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const { rules } = this;
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for (const [predicate, handler] of rules) {
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const predicate_result = predicate(item);
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// NOTE: to return a falsy predicate_result as a positive hit you must wrap it in something
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if (predicate_result) {
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return { handler, predicate_result };
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}
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}
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}
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}
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export class RegExp_Resolver extends Predicate_Resolver {
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constructor(rules=[]) {
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// NOTE: Rules should be iterable as [predicate, handler] pairs
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super();
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Object.assign(this, {
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rules: rules.map(([pattern, handler]) => [(str) => str.match(pattern), handler])
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});
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}
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}
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export class Mapping_Resolver extends Abstract_Resolver {
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constructor(rules=new Map(), key_function=null) {
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super();
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Object.assign(this, { rules, key_function });
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}
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resolve_handler(item) {
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const { key_function, rules } = this;
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const key = key_function ? key_function(item) : item;
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return rules.get(key);
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}
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}
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