added hash function to save prior states that get overwrriten in presBox restoreTarget

1 files changed, 4 insertions, 0 deletions

diff --git a/src/Utils.ts b/src/Utils.ts
index 852083834..502cf7db7 100644
--- a/src/Utils.ts
+++ b/src/Utils.ts
@@ -514,6 +514,10 @@ export function intersectRect(r1: { left: number; top: number; width: number; he
     return !(r2.left > r1.left + r1.width || r2.left + r2.width < r1.left || r2.top > r1.top + r1.height || r2.top + r2.height < r1.top);
 }
 
+export function stringHash(s?:string) {
+    return !s? undefined:  Math.abs(s.split('').reduce((a: any, b: any) => ((a) => a & a)((a << 5) - a + b.charCodeAt(0)),0));
+}
+
 export function percent2frac(percent: string) {
     return Number(percent.substr(0, percent.length - 1)) / 100;
 }