proxy-lens/dist/index.js

A type safe functional lens implemented via proxy

"use strict";
var __spreadArrays = (this && this.__spreadArrays) || function () {
    for (var s = 0, i = 0, il = arguments.length; i < il; i++) s += arguments[i].length;
    for (var r = Array(s), k = 0, i = 0; i < il; i++)
        for (var a = arguments[i], j = 0, jl = a.length; j < jl; j++, k++)
            r[k] = a[j];
    return r;
};
Object.defineProperty(exports, "__esModule", { value: true });
exports.lens = void 0;
function baseLens(get, set, root) {
    return {
        get: function (target) { return get((target !== null && target !== void 0 ? target : root)); },
        set: function (value, target) { return set(value, (target !== null && target !== void 0 ? target : root)); },
        let: function (value) {
            return proxyLens(function (target) { return set(value, target); }, function (value) { return value; }, root);
        },
        peg: function (get_) {
            return proxyLens(function (target) { return set(get_(set(get(target), target)), target); }, function (value) { return set(get_(set(get(value), value)), value); }, root);
        },
        mod: function (get_) {
            return proxyLens(function (target) { return set(get_(get(target)), target); }, function (value) { return set(get_(get(value)), value); }, root);
        },
        iso: function (get_, set_) {
            return proxyLens(function (target) { return get_(get(target)); }, function (value, target) { return set(set_(value, get(target)), target); }, root);
        },
    };
}
function arrayLens(get, set, root) {
    return {
        del: function (index) {
            return proxyLens(function (target) {
                return set((function () {
                    var _a;
                    var copy = ((_a = get(target)) !== null && _a !== void 0 ? _a : []).slice();
                    copy.splice(index, 1);
                    return copy;
                })(), target);
            }, function (value) { return value; }, root);
        },
        put: function (index, value) {
            return proxyLens(function (target) {
                return set((function () {
                    var _a;
                    var copy = ((_a = get(target)) !== null && _a !== void 0 ? _a : []).slice();
                    copy.splice.apply(copy, __spreadArrays([index < 0 ? copy.length + 1 + index : index,
                        0], (Array.isArray(value) ? value : [value])));
                    return copy;
                })(), target);
            }, function (value) { return value; }, root);
        },
        map: function (get_) {
            return proxyLens(function (target) { var _a; return set(((_a = get(target)) !== null && _a !== void 0 ? _a : []).map(get_), target); }, function (values) { return set(get(values).map(get_), values); }, root);
        },
        tap: function (get_) {
            return proxyTraversal(function (target) { var _a; return ((_a = get(target)) !== null && _a !== void 0 ? _a : []).filter(get_ !== null && get_ !== void 0 ? get_ : (function (_) { return true; })); }, function (values, target) {
                var _a;
                return set(((_a = get(target)) !== null && _a !== void 0 ? _a : []).reduce(function (_a, item) {
                    var _b;
                    var iterator = _a.iterator, value = _a.result;
                    return ({
                        iterator: iterator,
                        result: __spreadArrays(value, [
                            (get_ !== null && get_ !== void 0 ? get_ : (function (_) { return true; }))(item)
                                ? (_b = iterator.next().value) !== null && _b !== void 0 ? _b : item : item,
                        ]),
                    });
                }, { iterator: values[Symbol.iterator](), result: [] }).result, target);
            }, root);
        },
    };
}
function getTarget(key) {
    return (key.toString().match(/^\+?(0|[1-9]\d*)$/) ? [] : {});
}
function dispatch(key, get, set, root) {
    var _a;
    return ((_a = arrayLens(get, set, root)[key]) !== null && _a !== void 0 ? _a : baseLens(get, set, root)[key]);
}
function proxyLens(get, set, root) {
    return new Proxy(get, {
        apply: function (_, __, args) { return get(root !== null && root !== void 0 ? root : args[0]); },
        get: function (_, key) {
            return dispatch(key, get, set, root) ||
                proxyLens(function (target) {
                    return Object.assign(getTarget(key), get(target))[key];
                }, function (value, target) {
                    var _a;
                    return set(Object.assign(getTarget(key), get(target), (_a = {},
                        _a[key] = value,
                        _a)), target);
                }, root);
        },
    });
}
function proxyTraversal(get, set, root) {
    return new Proxy(get, {
        get: function (_, key) {
            return dispatch(key, get, set, root) ||
                proxyLens(function (target) {
                    return get(target).map(function (item) {
                        return Object.assign(getTarget(key), item)[key];
                    });
                }, function (values, target) {
                    return set(values.reduce(function (_a, value) {
                        var _b;
                        var iterator = _a.iterator, result = _a.result;
                        return ({
                            iterator: iterator,
                            result: __spreadArrays(result, [
                                Object.assign(getTarget(key), iterator.next().value, (_b = {},
                                    _b[key] = value,
                                    _b)),
                            ]),
                        });
                    }, {
                        iterator: get(target)[Symbol.iterator](),
                        result: [],
                    }).result, target);
                }, root);
        },
    });
}
function lens(root) {
    return proxyLens(function (target) { return target; }, function (value) { return value; }, root);
}
exports.lens = lens;
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