Re-add autoscale_cb.js

Author: chemcoder-2020

.gitignore

@@ -2,4 +2,3 @@
 .env
 /dist
 *.pyc
-*.js

stratback/backtesting/autoscale_cb.js

@@ -0,0 +1,35 @@
+if (!window._bt_scale_range) {
+    window._bt_scale_range = function (range, min, max, pad) {
+        "use strict";
+        if (min !== Infinity && max !== -Infinity) {
+            pad = pad ? (max - min) * .03 : 0;
+            range.start = min - pad;
+            range.end = max + pad;
+        } else console.error('backtesting: scale range error:', min, max, range);
+    };
+}
+
+clearTimeout(window._bt_autoscale_timeout);
+
+window._bt_autoscale_timeout = setTimeout(function () {
+    /**
+     * @variable cb_obj `fig_ohlc.x_range`.
+     * @variable source `ColumnDataSource`
+     * @variable ohlc_range `fig_ohlc.y_range`.
+     * @variable volume_range `fig_volume.y_range`.
+     */
+    "use strict";
+
+    let i = Math.max(Math.floor(cb_obj.start), 0),
+        j = Math.min(Math.ceil(cb_obj.end), source.data['ohlc_high'].length);
+
+    let max = Math.max.apply(null, source.data['ohlc_high'].slice(i, j)),
+        min = Math.min.apply(null, source.data['ohlc_low'].slice(i, j));
+    _bt_scale_range(ohlc_range, min, max, true);
+
+    if (volume_range) {
+        max = Math.max.apply(null, source.data['Volume'].slice(i, j));
+        _bt_scale_range(volume_range, 0, max * 1.03, false);
+    }
+
+}, 50);