Prevent infinity in line example, unused utils (#454)

Author: kurkle

docs/samples/charts/bar.md

@@ -92,27 +92,6 @@ const config = {
 };
 /* </block:config> */
 
-// <block:utils:4>
-function minValue(ctx) {
-  const dataset = ctx.chart.data.datasets[0];
-  return dataset.data.reduce((max, point) => Math.min(point, max), Infinity);
-}
-
-function maxValue(ctx) {
-  const datasets = ctx.chart.data.datasets;
-  const count = datasets[0].data.length;
-  let max = 0;
-  for (let i = 0; i < count; i++) {
-    let sum = 0;
-    for (const dataset of datasets) {
-      sum += dataset.data[i];
-    }
-    max = Math.max(max, sum);
-  }
-  return max;
-}
-// </block:utils>
-
 var actions = [
   {
     name: 'Randomize',

docs/samples/types/line.md

@@ -83,7 +83,8 @@ const config = {
 // <block:utils:3>
 function minValue(ctx) {
   const dataset = ctx.chart.data.datasets[0];
-  return dataset.data.reduce((max, point) => Math.min(point, max), Infinity);
+  const min = dataset.data.reduce((max, point) => Math.min(point, max), Infinity);
+  return isFinite(min) ? min : 0;
 }
 
 function maxValue(ctx) {