Add every.

README.md

@@ -180,6 +180,22 @@ Create a new `Channel` from an iterable or a [Node.js readable stream](https://n
 
 ### Channel Object
 
+#### every (callbackfn[, thisArg]) -> async Boolean
+
+`callbackfn` should be a function that accepts one argument and returns a value
+that is coercible to the Boolean values `true` or `false`.  `every` calls
+`callbackfn` once for each value present in the channel until it finds one where
+`callbackfn` returns `false`. If such a value is found, every immediately
+returns `false`. Otherwise, if `callbackfn` returned `true` for all elements,
+`every` will return `true`.
+
+If a `thisArg` parameter is provided, it will be used as the `this` value for
+each invocation of `callbackfn`. If it is not provided, `undefined` is used
+instead.
+
+Unlike in the Array version of `every`, `callbackfn` is called with only one
+argument.
+
 #### filter(callbackfn[, thisArg]) -> Channel
 #### forEach(callbackfn[, thisArg]) -> async
 

lib/index.js

@@ -103,6 +103,20 @@ const Channel = function (bufferLength = 0) {
   }
 
   const readOnly = Object.freeze({
+    every: async (callbackfn, thisArg) => {
+      for (;;) {
+        const value = await readOnly.shift()
+
+        if (value === undefined) {
+          return true
+        } else {
+          if (!callbackfn.call(thisArg, value)) {
+            return false
+          }
+        }
+      }
+    },
+
     filter: (callbackfn, thisArg) => {
       const output = Channel()
 

test/index.js

@@ -180,6 +180,12 @@ describe(`Channel object`, function () {
     })
   })
 
+  it(`every`, async function () {
+    const even = (number) => number % 2 === 0
+    assert(!await Channel.of(0, 1, 2).every(even))
+    assert(await Channel.of(0, 2, 4).every(even))
+  })
+
   it(`filter`, async function () {
     assert.deepEqual(
       await toArray(Channel.of(0, 1, 2, 3, 4, 5)