function every(coll, iteratee, callback) {
        return _createTester(bool => !bool, res => !res)(eachOf$1, coll, iteratee, callback)
    }
Returns `true` if every element in `coll` satisfies an async test. If any
iteratee call returns `false`, the main `callback` is immediately called.

@name every
@static
@memberOf module:Collections
@method
@alias all
@category Collection
@param {Array|Iterable|AsyncIterable|Object} coll - A collection to iterate over.
@param {AsyncFunction} iteratee - An async truth test to apply to each item
in the collection in parallel.
The iteratee must complete with a boolean result value.
Invoked with (item, callback).
@param {Function} [callback] - A callback which is called after all the
`iteratee` functions have finished. Result will be either `true` or `false`
depending on the values of the async tests. Invoked with (err, result).
@returns {Promise} a promise, if no callback provided
@example

// dir1 is a directory that contains file1.txt, file2.txt
// dir2 is a directory that contains file3.txt, file4.txt
// dir3 is a directory that contains file5.txt
// dir4 does not exist

const fileList = ['dir1/file1.txt','dir2/file3.txt','dir3/file5.txt'];
const withMissingFileList = ['file1.txt','file2.txt','file4.txt'];

// asynchronous function that checks if a file exists
function fileExists(file, callback) {
   fs.access(file, fs.constants.F_OK, (err) => {
       callback(null, !err);
   });
}

// Using callbacks
async.every(fileList, fileExists, function(err, result) {
    console.log(result);
    // true
    // result is true since every file exists
});

async.every(withMissingFileList, fileExists, function(err, result) {
    console.log(result);
    // false
    // result is false since NOT every file exists
});

// Using Promises
async.every(fileList, fileExists)
.then( result => {
    console.log(result);
    // true
    // result is true since every file exists
}).catch( err => {
    console.log(err);
});

async.every(withMissingFileList, fileExists)
.then( result => {
    console.log(result);
    // false
    // result is false since NOT every file exists
}).catch( err => {
    console.log(err);
});

// Using async/await
async () => {
    try {
        let result = await async.every(fileList, fileExists);
        console.log(result);
        // true
        // result is true since every file exists
    }
    catch (err) {
        console.log(err);
    }
}

async () => {
    try {
        let result = await async.every(withMissingFileList, fileExists);
        console.log(result);
        // false
        // result is false since NOT every file exists
    }
    catch (err) {
        console.log(err);
    }
}