variant/lib/sequence.js

Variant types (a.k.a. Discriminated Unions) in TypeScript

"use strict";
/**
 * What should a progression do?
 *
 *  - Be able to create a variant
 *      - maybe this isn't necessary.
 *  - do a .compare(a: T, b: T) and get back a number;
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.sequence = exports.CompareResult = void 0;
const remote_1 = require("./remote");
const variant_1 = require("./variant");
var CompareResult;
(function (CompareResult) {
    CompareResult[CompareResult["Lesser"] = -1] = "Lesser";
    CompareResult[CompareResult["Equal"] = 0] = "Equal";
    CompareResult[CompareResult["Greater"] = 1] = "Greater";
})(CompareResult = exports.CompareResult || (exports.CompareResult = {}));
;
function _sequenceFromScratch(list) {
    const mod = variant_1.variantList(list);
    const order = list.map(i => getType(i));
    const seq = sequence(mod, order);
    return seq;
}
function _sequence(vmod, order) {
    let rawStringOrder = order.map(i => typeof i === 'string' ? i : i.type);
    const restrictedVmod = Object.keys(vmod).reduce((acc, key) => {
        return Object.assign(Object.assign({}, acc), { [key]: vmod[key] });
    }, {});
    const keyType = Object.values(vmod)[0].key;
    return Object.assign(Object.assign({}, remote_1.remote(restrictedVmod, keyType)), { length: order.length, compare: (a, b) => {
            const ai = rawStringOrder.findIndex(i => i === getType(a, keyType));
            const bi = rawStringOrder.findIndex(i => i === getType(b, keyType));
            const diff = ai - bi;
            return diff === 0 ? diff : (diff / Math.abs(diff));
        }, get(i) {
            const type = this.types[i];
            return this.new[type];
        }, index: a => rawStringOrder.findIndex(i => i === getType(a)), types: rawStringOrder });
}
function sequence(...args) {
    if (Array.isArray(args[0])) {
        const [list] = args;
        return _sequenceFromScratch(list);
    }
    else {
        const [vmod, list] = args;
        return _sequence(vmod, list);
    }
}
exports.sequence = sequence;
function getType(object, typeKey) {
    const key = typeKey !== null && typeKey !== void 0 ? typeKey : 'type';
    if (typeof object === 'string') {
        return object;
    }
    else {
        if (typeof object === 'function') {
            return object.type;
        }
        else {
            return object[key];
        }
    }
}
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