save WIP

vue/src/utils/fractions.js

@@ -0,0 +1,63 @@
+/* frac.js (C) 2012-present SheetJS -- http://sheetjs.com */
+
+/*https://developer.aliyun.com/mirror/npm/package/frac/v/0.3.0 Apache license*/
+export function frac(x, D, mixed) {
+    var n1 = Math.floor(x), d1 = 1;
+    var n2 = n1 + 1, d2 = 1;
+    if (x !== n1) while (d1 <= D && d2 <= D) {
+        var m = (n1 + n2) / (d1 + d2);
+        if (x === m) {
+            if (d1 + d2 <= D) {
+                d1 += d2;
+                n1 += n2;
+                d2 = D + 1;
+            } else if (d1 > d2) d2 = D + 1;
+            else d1 = D + 1;
+            break;
+        } else if (x < m) {
+            n2 = n1 + n2;
+            d2 = d1 + d2;
+        } else {
+            n1 = n1 + n2;
+            d1 = d1 + d2;
+        }
+    }
+    if (d1 > D) {
+        d1 = d2;
+        n1 = n2;
+    }
+    if (!mixed) return [0, n1, d1];
+    var q = Math.floor(n1 / d1);
+    return [q, n1 - q * d1, d1];
+}
+
+export function cont(x, D, mixed) {
+    var sgn = x < 0 ? -1 : 1;
+    var B = x * sgn;
+    var P_2 = 0, P_1 = 1, P = 0;
+    var Q_2 = 1, Q_1 = 0, Q = 0;
+    var A = Math.floor(B);
+    while (Q_1 < D) {
+        A = Math.floor(B);
+        P = A * P_1 + P_2;
+        Q = A * Q_1 + Q_2;
+        if ((B - A) < 0.00000005) break;
+        B = 1 / (B - A);
+        P_2 = P_1;
+        P_1 = P;
+        Q_2 = Q_1;
+        Q_1 = Q;
+    }
+    if (Q > D) {
+        if (Q_1 > D) {
+            Q = Q_2;
+            P = P_2;
+        } else {
+            Q = Q_1;
+            P = P_1;
+        }
+    }
+    if (!mixed) return [0, sgn * P, Q];
+    var q = Math.floor(sgn * P / Q);
+    return [q, sgn * P - q * Q, Q];
+}

vue/src/utils/utils.js

@@ -61,4 +61,38 @@ export const ResolveUrlMixin = {
 
 export function resolveDjangoUrl(url, params) {
     return window.Urls[url](params)
-}
+}
+
+/*
+* other utilities
+* */
+
+export function getUserPreference(pref) {
+    return window.USER_PREF[pref]
+}
+
+import {frac} from "@/utils/fractions";
+
+export function calculateAmount(amount, factor) {
+    if (getUserPreference('user_fractions')) {
+        let return_string = ''
+        let fraction = frac.cont((amount * factor), 9, true)
+
+        if (fraction[0] > 0) {
+            return_string += fraction[0]
+        }
+
+        if (fraction[1] > 0) {
+            return_string += ` <sup>${(fraction[1])}</sup>&frasl;<sub>${(fraction[2])}</sub>`
+        }
+
+        return return_string
+    } else {
+        return roundDecimals(amount * factor)
+    }
+}
+
+export function roundDecimals(num) {
+    let decimals = ((getUserPreference('user_fractions')) ? getUserPreference('user_fractions') : 2);
+    return +(Math.round(num + `e+${decimals}`) + `e-${decimals}`);
+}