--- id: a10d2431ad0c6a099a4b8b52 title: Everything Be True challengeType: 5 forumTopicId: 16011 dashedName: everything-be-true --- # --description-- Check if the predicate (second argument) is truthy on all elements of a collection (first argument). In other words, you are given an array collection of objects. The predicate `pre` will be an object property and you need to return `true` if its value is `truthy`. Otherwise, return `false`. In JavaScript, `truthy` values are values that translate to `true` when evaluated in a Boolean context. Remember, you can access object properties through either dot notation or `[]` notation. # --hints-- `truthCheck([{name: "Quincy", role: "Founder", isBot: false}, {name: "Naomi", role: "", isBot: false}, {name: "Camperbot", role: "Bot", isBot: true}], "isBot")` should return `false`. ```js assert.strictEqual(truthCheck( [ { name: "Quincy", role: "Founder", isBot: false }, { name: "Naomi", role: "", isBot: false }, { name: "Camperbot", role: "Bot", isBot: true } ], "isBot"), false); ``` `truthCheck([{name: "Quincy", role: "Founder", isBot: false}, {name: "Naomi", role: "", isBot: false}, {name: "Camperbot", role: "Bot", isBot: true}], "name")` should return `true`. ```js assert.strictEqual(truthCheck( [ { name: "Quincy", role: "Founder", isBot: false }, { name: "Naomi", role: "", isBot: false }, { name: "Camperbot", role: "Bot", isBot: true } ], "name"), true); ``` `truthCheck([{name: "Quincy", role: "Founder", isBot: false}, {name: "Naomi", role: "", isBot: false}, {name: "Camperbot", role: "Bot", isBot: true}], "role")` should return `false`. ```js assert.strictEqual(truthCheck( [ { name: "Quincy", role: "Founder", isBot: false }, { name: "Naomi", role: "", isBot: false }, { name: "Camperbot", role: "Bot", isBot: true } ], "role"), false); ``` `truthCheck([{name: "Pikachu", number: 25, caught: 3}, {name: "Togepi", number: 175, caught: 1}], "number")` should return `true`. ```js assert.strictEqual(truthCheck( [ { name: "Pikachu", number: 25, caught: 3 }, { name: "Togepi", number: 175, caught: 1 }, ], "number"), true); ``` `truthCheck([{name: "Pikachu", number: 25, caught: 3}, {name: "Togepi", number: 175, caught: 1}, {name: "MissingNo", number: NaN, caught: 0}], "caught")` should return `false`. ```js assert.strictEqual(truthCheck( [ { name: "Pikachu", number: 25, caught: 3 }, { name: "Togepi", number: 175, caught: 1 }, { name: "MissingNo", number: NaN, caught: 0 }, ], "caught"), false); ``` `truthCheck([{name: "Pikachu", number: 25, caught: 3}, {name: "Togepi", number: 175, caught: 1}, {name: "MissingNo", number: NaN, caught: 0}], "number")` should return `false`. ```js assert.strictEqual(truthCheck( [ { name: "Pikachu", number: 25, caught: 3 }, { name: "Togepi", number: 175, caught: 1 }, { name: "MissingNo", number: NaN, caught: 0 }, ], "number"), false); ``` `truthCheck([{name: "Quincy", username: "QuincyLarson"}, {name: "Naomi", username: "nhcarrigan"}, {name: "Camperbot"}], "username")` should return `false`. ```js assert.strictEqual(truthCheck( [ { name: "Quincy", username: "QuincyLarson" }, { name: "Naomi", username: "nhcarrigan" }, { name: "Camperbot" } ], "username"), false); ``` `truthCheck([{name: "freeCodeCamp", users: [{name: "Quincy"}, {name: "Naomi"}]}, {name: "Code Radio", users: [{name: "Camperbot"}]}, {name: "", users: []}], "users")` should return `true`. ```js assert.strictEqual(truthCheck( [ { name: "freeCodeCamp", users: [{ name: "Quincy" }, { name: "Naomi" }] }, { name: "Code Radio", users: [{ name: "Camperbot" }] }, { name: "", users: [] }, ], "users"), true); ``` `truthCheck([{id: 1, data: {url: "https://freecodecamp.org", name: "freeCodeCamp"}}, {id: 2, data: {url: "https://coderadio.freecodecamp.org/", name: "CodeRadio"}}, {id: null, data: {}}], "data")` should return `true`. ```js assert.strictEqual(truthCheck( [ { id: 1, data: { url: "https://www.freecodecamp.org", name: "freeCodeCamp" } }, { id: 2, data: { url: "https://coderadio.freecodecamp.org/", name: "CodeRadio" } }, { id: null, data: {} }, ], "data"), true); ``` `truthCheck([{id: 1, data: {url: "https://freecodecamp.org", name: "freeCodeCamp"}}, {id: 2, data: {url: "https://coderadio.freecodecamp.org/", name: "CodeRadio"}}, {id: null, data: {}}], "id")` should return `false`. ```js assert.strictEqual(truthCheck( [ { id: 1, data: { url: "https://www.freecodecamp.org", name: "freeCodeCamp" } }, { id: 2, data: { url: "https://coderadio.freecodecamp.org/", name: "CodeRadio" } }, { id: null, data: {} }, ], "id"), false); ``` # --seed-- ## --seed-contents-- ```js function truthCheck(collection, pre) { return pre; } truthCheck([{name: "Quincy", role: "Founder", isBot: false}, {name: "Naomi", role: "", isBot: false}, {name: "Camperbot", role: "Bot", isBot: true}], "isBot"); ``` # --solutions-- ```js function truthCheck(collection, pre) { return collection.every(function(e) { return e[pre]; }); } ```