function mergeScaleConfig(/* config objects ... */) {
	return helpers$1.merge(Object.create(null), [].slice.call(arguments), {
		merger: function(key, target, source, options) {
			if (key === 'xAxes' || key === 'yAxes') {
				var slen = source[key].length;
				var i, type, scale;

				if (!target[key]) {
					target[key] = [];
				}

				for (i = 0; i < slen; ++i) {
					scale = source[key][i];
					type = valueOrDefault$9(scale.type, key === 'xAxes' ? 'category' : 'linear');

					if (i >= target[key].length) {
						target[key].push({});
					}

					if (!target[key][i].type || (scale.type && scale.type !== target[key][i].type)) {
						// new/untyped scale or type changed: let's apply the new defaults
						// then merge source scale to correctly overwrite the defaults.
						helpers$1.merge(target[key][i], [core_scaleService.getScaleDefaults(type), scale]);
					} else {
						// scales type are the same
						helpers$1.merge(target[key][i], scale);
					}
				}
			} else {
				helpers$1._merger(key, target, source, options);
			}
		}
	});
}
Recursively merge the given config objects representing the `scales` option
by incorporating scale defaults in `xAxes` and `yAxes` array items, then
returns a deep copy of the result, thus doesn't alter inputs.