Move order utils to @0xproject/order-utils

1 files changed, 18 insertions, 0 deletions

diff --git a/packages/order-utils/src/salt.ts b/packages/order-utils/src/salt.ts
new file mode 100644
index 000000000..90a4197c0
--- /dev/null
+++ b/packages/order-utils/src/salt.ts
@@ -0,0 +1,18 @@
+import { BigNumber } from '@0xproject/utils';
+
+const MAX_DIGITS_IN_UNSIGNED_256_INT = 78;
+
+/**
+ * Generates a pseudo-random 256-bit salt.
+ * The salt can be included in a 0x order, ensuring that the order generates a unique orderHash
+ * and will not collide with other outstanding orders that are identical in all other parameters.
+ * @return  A pseudo-random 256-bit number that can be used as a salt.
+ */
+export function generatePseudoRandomSalt(): BigNumber {
+    // BigNumber.random returns a pseudo-random number between 0 & 1 with a passed in number of decimal places.
+    // Source: https://mikemcl.github.io/bignumber.js/#random
+    const randomNumber = BigNumber.random(MAX_DIGITS_IN_UNSIGNED_256_INT);
+    const factor = new BigNumber(10).pow(MAX_DIGITS_IN_UNSIGNED_256_INT - 1);
+    const salt = randomNumber.times(factor).round();
+    return salt;
+}