Add more examples

Author: jessealama

examples/pow.js

@@ -6,8 +6,8 @@ function pow(a, b) {
     let i = one;
     let result = a;
     while (-1 === i.cmp(b)) {
-        result = Decimal128.multiply(result, a);
-        i = Decimal128.add(i, one);
+        result = result.multiply(a);
+        i = i.add(one);
     }
     return result;
 }

examples/round.js

@@ -1 +1,72 @@
 // Example with different rounding modes
+
+// Examples from the Intl.NumberFormat spec
+
+let minusOnePointFive = new Decimal128("-1.5");
+let zeroPointFour = new Decimal128("0.4");
+let zeroPointFive = new Decimal128("0.5");
+let zeroPointSix = new Decimal128("0.6");
+let onePointFive = new Decimal128("1.5");
+
+// ceiling
+"-1" === minusOnePointFive.round(0, "ceil").toString();
+"1" === zeroPointFour.round(0, "ceil").toString();
+"1" === zeroPointFive.round(0, "ceil").toString();
+"1" === zeroPointSix.round(0, "ceil").toString();
+"2" === onePointFive.round(0, "ceil").toString();
+
+// floor
+"-2" === minusOnePointFive.round(0, "floor").toString();
+"0" === zeroPointFour.round(0, "floor").toString();
+"0" === zeroPointFive.round(0, "floor").toString();
+"0" === zeroPointSix.round(0, "floor").toString();
+"1" === onePointFive.round(0, "floor").toString();
+
+// expand
+"-2" === minusOnePointFive.round(0, "expand").toString();
+"1" === zeroPointFour.round(0, "expand").toString();
+"1" === zeroPointFive.round(0, "expand").toString();
+"1" === zeroPointSix.round(0, "expand").toString();
+"2" === onePointFive.round(0, "expand").toString();
+
+// truncate
+"-1" === minusOnePointFive.round(0, "trunc").toString();
+"0" === zeroPointFour.round(0, "trunc").toString();
+"0" === zeroPointFive.round(0, "trunc").toString();
+"0" === zeroPointSix.round(0, "trunc").toString();
+"1" === onePointFive.round(0, "trunc").toString();
+
+// round ties to ceiling
+"-1" === minusOnePointFive.round(0, "halfCeil").toString();
+"0" === zeroPointFour.round(0, "halfCeil").toString();
+"1" === zeroPointFive.round(0, "halfCeil").toString();
+"1" === zeroPointSix.round(0, "halfCeil").toString();
+"2" === onePointFive.round(0, "halfCeil").toString();
+
+// round ties to floor
+"-2" === minusOnePointFive.round(0, "halfFloor").toString();
+"0" === zeroPointFour.round(0, "halfFloor").toString();
+"0" === zeroPointFive.round(0, "halfFloor").toString();
+"1" === zeroPointSix.round(0, "halfFloor").toString();
+"1" === onePointFive.round(0, "halfFloor").toString();
+
+// round ties away from zero
+"-2" === minusOnePointFive.round(0, "halfExpand").toString();
+"0" === zeroPointFour.round(0, "halfExpand").toString();
+"1" === zeroPointFive.round(0, "halfExpand").toString();
+"1" === zeroPointSix.round(0, "halfExpand").toString();
+"2" === onePointFive.round(0, "halfExpand").toString();
+
+// round ties to toward zero
+"-1" === minusOnePointFive.round(0, "halfTrunc").toString();
+"0" === zeroPointFour.round(0, "halfTrunc").toString();
+"0" === zeroPointFive.round(0, "halfTrunc").toString();
+"1" === zeroPointSix.round(0, "halfTrunc").toString();
+"1" === onePointFive.round(0, "halfTrunc").toString();
+
+// round ties to even
+"-2" === minusOnePointFive.round(0, "halfEven").toString();
+"0" === zeroPointFour.round(0, "halfEven").toString();
+"0" === zeroPointFive.round(0, "halfEven").toString();
+"1" === zeroPointSix.round(0, "halfEven").toString();
+"2" === onePointFive.round(0, "halfEven").toString();

examples/step.js

@@ -1 +1,14 @@
 // Example for stepping a value up/down
+import { pow } from "./pow.js";
+import { Decimal128 } from "../src/decimal128.mjs";
+
+const ten = new Decimal128("10");
+
+function stepUp(d, n, x) {
+    let increment = pow(ten, x);
+    return d.add(n.times(increment));
+}
+
+let starting = new Decimal128("1.23");
+let stepped = stepUp(starting, new Decimal128("3"), new Decimal("-4"));
+console.log(stepped.toFixed(4)); // 1.2305