css-select/dist/pseudo-selectors/index.js

a CSS selector compiler/engine

/*
 * Pseudo selectors
 *
 * Pseudo selectors are available in three forms:
 *
 * 1. Filters are called when the selector is compiled and return a function
 *  that has to return either false, or the results of `next()`.
 * 2. Pseudos are called on execution. They have to return a boolean.
 * 3. Subselects work like filters, but have an embedded selector that will be run separately.
 *
 * Filters are great if you want to do some pre-processing, or change the call order
 * of `next()` and your code.
 * Pseudos should be used to implement simple checks.
 */
import { parse } from "css-what";
import { aliases } from "./aliases.js";
import { filters } from "./filters.js";
import { pseudos, verifyPseudoArguments } from "./pseudos.js";
import { subselects } from "./subselects.js";
/**
 * Compile a pseudo selector into an executable query function.
 * @param next Matcher to run after this matcher succeeds.
 * @param selector Selector used to match elements.
 * @param options Options that control this operation.
 * @param context Context nodes used to scope selector matching.
 * @param compileToken Function used to compile nested selector tokens.
 */
export function compilePseudoSelector(next, selector, options, context, compileToken) {
    const { name, data } = selector;
    if (Array.isArray(data)) {
        if (!(name in subselects)) {
            throw new Error(`Unknown pseudo-class :${name}(${data})`);
        }
        return subselects[name](next, data, options, context, compileToken);
    }
    const userPseudo = options.pseudos?.[name];
    const stringPseudo = typeof userPseudo === "string" ? userPseudo : aliases[name];
    if (typeof stringPseudo === "string") {
        if (data != null) {
            throw new Error(`Pseudo ${name} doesn't have any arguments`);
        }
        // The alias has to be parsed here, to make sure options are respected.
        const alias = parse(stringPseudo);
        return subselects["is"](next, alias, options, context, compileToken);
    }
    if (typeof userPseudo === "function") {
        verifyPseudoArguments(userPseudo, name, data, 1);
        return (element) => userPseudo(element, data) && next(element);
    }
    if (name in filters) {
        return filters[name](next, data, options, context, compileToken);
    }
    if (name in pseudos) {
        const pseudo = pseudos[name];
        verifyPseudoArguments(pseudo, name, data, 2);
        return (element) => pseudo(element, options, data) && next(element);
    }
    throw new Error(`Unknown pseudo-class :${name}`);
}
export { aliases } from "./aliases.js";
export { filters } from "./filters.js";
export { pseudos } from "./pseudos.js";
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