feat(ChartInternal,Options): Add before/after initialization callbacks

Add two new callbacks for before and after initialization.

Fix #55
Close #126

spec/core-spec.js

@@ -50,6 +50,45 @@ describe("CORE", function() {
 		});
 	});
 
+	describe("init callbacks", () => {
+		let oninit = false;
+		let onbeforeinit = false;
+		let onafterinit = false;
+
+		before(() => {
+			args = {
+				data: {
+					columns: [
+						["data1", 30, 200, 100, 400, 150, 250],
+						["data2", 50, 20, 10, 40, 15, 25],
+						["data3", 150, 120, 110, 140, 115, 125]
+					]
+				},
+				oninit: () => {
+					oninit = true;
+				},
+				onbeforeinit: () => {
+					onbeforeinit = true;
+				},
+				onafterinit: () => {
+					onafterinit = true;
+				}
+			}
+		});
+
+		it("check for oninit callback", () => {
+			expect(oninit).to.be.true;
+		});
+
+		it("check for onbeforeinit callback", () => {
+			expect(onbeforeinit).to.be.true;
+		});
+
+		it("check for onafterinit callback", () => {
+			expect(onafterinit).to.be.true;
+		});
+	});
+
 	describe("size", () => {
 		it("should have same width", () => {
 			const svg = d3.select("#chart svg");

src/config/Options.js

@@ -233,6 +233,19 @@ export default class Options {
 			 */
 			onresized: () => {},
 
+			/**
+			 * Set a callback to execute before the chart is initialized
+			 * @name onbeforeinit
+			 * @memberof Options
+			 * @type {Function}
+			 * @default function(){}
+			 * @example
+			 * onbeforeinit: function() {
+			 *   ...
+			 * }
+			 */
+			onbeforeinit: undefined,
+
 			/**
 			 * Set a callback to execute when the chart is initialized.
 			 * @name oninit
@@ -246,6 +259,19 @@ export default class Options {
 			 */
 			oninit: () => {},
 
+			/**
+			 * Set a callback to execute after the chart is initialized
+			 * @name onafterinit
+			 * @memberof Options
+			 * @type {Function}
+			 * @default function(){}
+			 * @example
+			 * onafterinit: function() {
+			 *   ...
+			 * }
+			 */
+			onafterinit: undefined,
+
 			/**
 			 * Set a callback which is executed when the chart is rendered. Basically, this callback will be called in each time when the chart is redrawed.
 			 * @name onrendered
@@ -2299,4 +2325,3 @@ export default class Options {
 		};
 	}
 }
-

src/internals/ChartInternal.js

@@ -35,11 +35,21 @@ export default class ChartInternal {
 	}
 
 	beforeInit() {
+		const $$ = this;
+		const config = $$.config;
+
 		// can do something
+
+		isFunction(config.onbeforeinit) && config.onbeforeinit.call($$);
 	}
 
 	afterInit() {
+		const $$ = this;
+		const config = $$.config;
+
 		// can do something
+
+		isFunction(config.onafterinit) && config.onafterinit.call($$);
 	}
 
 	init() {