Merge pull request #1109 from GitbookIO/3.0.0

Version 3.0.0

1 files changed, 62 insertions, 0 deletions

diff --git a/lib/utils/promise.js b/lib/utils/promise.js
new file mode 100644
index 0000000..d49cf27
--- /dev/null
+++ b/lib/utils/promise.js
@@ -0,0 +1,62 @@
+var Q = require('q');
+var _ = require('lodash');
+
+// Reduce an array to a promise
+function reduce(arr, iter, base) {
+    return _.reduce(arr, function(prev, elem, i) {
+        return prev.then(function(val) {
+            return iter(val, elem, i);
+        });
+    }, Q(base));
+}
+
+// Transform an array
+function serie(arr, iter, base) {
+    return reduce(arr, function(before, item, i) {
+        return Q(iter(item, i))
+        .then(function(r) {
+            before.push(r);
+            return before;
+        });
+    }, []);
+}
+
+// Iter over an array and return first result (not null)
+function some(arr, iter) {
+    return _.reduce(arr, function(prev, elem, i) {
+        return prev.then(function(val) {
+            if (val) return val;
+
+            return iter(elem, i);
+        });
+    }, Q());
+}
+
+// Map an array using an async (promised) iterator
+function map(arr, iter) {
+    return reduce(arr, function(prev, entry, i) {
+        return Q(iter(entry, i))
+        .then(function(out) {
+            prev.push(out);
+            return prev;
+        });
+    }, []);
+}
+
+// Wrap a fucntion in a promise
+function wrap(func) {
+    return _.wrap(func, function(_func) {
+        var args = Array.prototype.slice.call(arguments, 1);
+        return Q()
+        .then(function() {
+            return _func.apply(null, args);
+        });
+    });
+}
+
+module.exports = Q;
+module.exports.reduce = reduce;
+module.exports.map = map;
+module.exports.serie = serie;
+module.exports.some = some;
+module.exports.wrapfn = wrap;