Add guarded array support
parent
d77b042299
commit
8ac9a02d2d
@ -0,0 +1,17 @@
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"use strict";
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const dm = require("../");
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let Thing = dm.createType("Thing", {
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value: dm.string()
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});
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let item = Thing({
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value: "foo"
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});
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console.log(item);
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delete item.value;
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console.log(item);
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@ -0,0 +1,136 @@
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"use strict";
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const errors = require("../errors");
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const getValueType = require("../util/get-value-type");
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let indexRegex = /^[0-9]+$/;
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module.exports = function createGuardedArray(array, guard, _, parent) {
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function generateArraySignatureError() {
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let wantedSignature = {
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_guardedCollectionType: "array",
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_itemType: guard._rule
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};
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return new errors.ValidationError(`Expected an array or ${getValueType(wantedSignature)}, got ${getValueType(array)} instead`);
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}
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if (array._guardedCollectionType === "array") {
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if (guard === array._itemType) {
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return array;
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} else {
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throw generateArraySignatureError();
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}
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} else if (Array.isArray(array)) {
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for (let value of array) {
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check(value);
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}
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/* We shallow-clone the array here, to keep users from accidentally mutating the source array outside the purview of the guards specified here. */
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let targetArray = array.slice();
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function check(value) {
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let guardResult = guard.call(parent, value);
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if (guardResult === true) {
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return true;
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} else {
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throw guardResult;
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}
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}
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let guardedForEach = guardedIterationMethod.bind(undefined, "forEach");
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let guardedFilter = guardedIterationMethod.bind(undefined, "filter");
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let guardedMap = guardedIterationMethod.bind(undefined, "map");
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let guardedSome = guardedIterationMethod.bind(undefined, "some");
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let guardedEvery = guardedIterationMethod.bind(undefined, "every");
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let guardedFind = guardedIterationMethod.bind(undefined, "find");
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let proxyAPI = {
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_guardedCollectionType: "array",
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_itemType: guard,
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push: guardedPush,
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reduce: guardedReduce,
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reduceRight: guardedReduceRight,
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filter: guardedFilter,
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map: guardedMap,
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forEach: guardedForEach,
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some: guardedSome,
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every: guardedEvery,
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find: guardedFind,
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unshift: guardedUnshift,
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fill: guardedFill,
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splice: guardedSplice
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};
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let proxy = new Proxy(targetArray, {
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get: function (target, property) {
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if (proxyAPI[property] != null) {
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return proxyAPI[property];
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} else {
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return target[property];
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}
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},
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set: function (target, property, value) {
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if (indexRegex.test(property)) {
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check(value);
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}
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target[property] = value;
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return true;
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}
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});
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function guardedUnshift(...items) {
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for (let item of items) {
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check(item);
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}
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return targetArray.unshift(...items);
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}
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function guardedPush(value) {
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if (check(value) === true) {
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return targetArray.push(value);
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}
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}
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function guardedFill(value) {
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if (check(value) === true) {
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return targetArray.fill(value);
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}
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}
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function guardedSplice(start, deleteCount, ...items) {
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for (let item of items) {
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check(item);
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}
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return targetArray.splice(start, deleteCount, ...items);
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}
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/* We provide the proxy instead of the original array as the 'array' argument for iteration functions, to prevent direct access to the underlying array; otherwise the user could accidentally mutate the underlying array from within a forEach callback, bypassing the validation requirements. */
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function guardedIterationMethod(method, callback, thisArg) {
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return targetArray[method]((value, index, _array) => {
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return callback(value, index, proxy);
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}, thisArg);
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}
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function guardedReduce(callback, initialValue) {
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return targetArray.reduce((accumulator, value, index, _array) => {
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return callback(accumulator, value, index, proxy);
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}, initialValue);
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}
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function guardedReduceRight(callback, initialValue) {
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return targetArray.reduceRight((accumulator, value, index, _array) => {
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return callback(accumulator, value, index, proxy);
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}, initialValue);
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}
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return proxy;
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} else {
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throw generateArraySignatureError();
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}
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};
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@ -0,0 +1,46 @@
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"use strict";
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const expect = require("chai").expect;
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const dm = require("../src");
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let User = dm.createType("User", {
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messages: dm.arrayOf(dm.string())
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});
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describe("guarded arrays", () => {
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let joe = User({
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messages: []
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});
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it("should accept valid values", () => {
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joe.messages.push("Hello world!");
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expect(joe.messages[0]).to.equal("Hello world!");
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joe.messages.splice(0, 0, "Hello earth!")
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expect(joe.messages[0]).to.equal("Hello earth!");
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expect(joe.messages[1]).to.equal("Hello world!");
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joe.messages[0] = "Hello moon!";
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console.log(joe.messages);
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expect(joe.messages[0]).to.equal("Hello moon!");
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expect(joe.messages[1]).to.equal("Hello world!");
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});
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it("should reject invalid values", () => {
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expect(() => {
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joe.messages.push(42);
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}).to.throw("Expected a string, got a number instead");
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expect(() => {
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joe.messages.splice(0, 0, 43);
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}).to.throw("Expected a string, got a number instead");
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expect(() => {
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joe.messages[0] = 44;
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}).to.throw("Expected a string, got a number instead");
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expect(joe.messages[0]).to.equal("Hello moon!");
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expect(joe.messages[1]).to.equal("Hello world!");
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});
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});
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