Support Async/Await based on #12

bublejs · Apr 10, 2018 · 578a849 · 578a849
1 parent fae708e
commit 578a849
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Showing 9 changed files with 157 additions and 56 deletions.
diff --git a/.eslintrc b/.eslintrc
@@ -5,6 +5,7 @@
         "semi": [ 2, "always" ],
         "keyword-spacing": [ 2, { "before": true, "after": true } ],
         "space-before-blocks": [ 2, "always" ],
+        "space-in-parens": [ 2, "never" ],
         "no-mixed-spaces-and-tabs": [ 2, "smart-tabs" ],
         "no-cond-assign": [ 0 ]
     },

diff --git a/src/index.js b/src/index.js
@@ -15,8 +15,8 @@ const dangerousTransforms = ['dangerousTaggedTemplateString', 'dangerousForOf'];
 export function target(target) {
 	const targets = Object.keys(target);
 	let bitmask = targets.length
-		? 0b11111111111111111111
-		: 0b01000000000000000000;
+		? 0b111111111111111111111
+		: 0b010000000000000000000;
 
 	Object.keys(target).forEach(environment => {
 		const versions = matrix[environment];

diff --git a/src/program/BlockStatement.js b/src/program/BlockStatement.js
@@ -176,6 +176,53 @@ export default class BlockStatement extends Node {
 
 		super.transpile(code, transforms);
 
+		if (transforms.asyncAwait && this.isFunctionBlock && this.parent.async && this.body.length) {
+			const first = this.body[0];
+			const last = this.body[this.body.length - 1];
+			const hasOnlyOneLine = this.body.length === 1;
+
+			// TODO refactor :)
+			if (this.parent.type === 'FunctionDeclaration') {
+				if (hasOnlyOneLine) {
+					if (first.type === 'ReturnStatement') {
+						code.insertLeft(first.argument.start, 'Promise.resolve().then(function() { ');
+						code.insertLeft(first.end, ' })');
+					} else {
+						code.insertLeft(first.start, 'return Promise.resolve().then(function() { ');
+						code.insertRight(last.end, ' }).then(function() {})');
+					}
+				} else {
+					code.insertLeft(first.start, 'return Promise.resolve()');
+					code.insertRight(last.end, '.then(function() {})');
+
+					for (let i = 0; i < this.body.length; i++) {
+						const prev = this.body[i - 1];
+						const cur = this.body[i];
+						const next = this.body[i + 1];
+
+						if (cur.expression.type === 'AwaitExpression') {
+							code.insertLeft(cur.start, '.then(function() { ');
+							code.insertRight(cur.end, ' })');
+						} else {
+							if (!prev || prev.expression.type === 'AwaitExpression') {
+								code.insertLeft(cur.start, '.then(function() { ');
+							}
+
+							if (!next || next.expression.type === 'AwaitExpression') {
+								code.insertRight(cur.end, ' })');
+							}
+						}
+					}
+				}
+
+			} else if (this.parent.type === 'ArrowFunctionExpression') {
+				// TODO merge with ^
+				// wrap the function's body in a promise
+				code.insertLeft(first.start + 1, 'Promise.resolve().then(function() { return ');
+				code.insertLeft(last.end, ' })');
+			}
+		}
+
 		if (this.createdDeclarations.length) {
 			introStatementGenerators.push((start, prefix, suffix) => {
 				const assignment = `${prefix}var ${this.createdDeclarations.join(', ')}${suffix}`;

diff --git a/src/program/types/ArrowFunctionExpression.js b/src/program/types/ArrowFunctionExpression.js
@@ -1,5 +1,6 @@
 import Node from '../Node.js';
 import removeTrailingComma from '../../utils/removeTrailingComma.js';
+import AwaitExpression from './AwaitExpression';
 
 export default class ArrowFunctionExpression extends Node {
 	initialise(transforms) {
@@ -18,6 +19,7 @@ export default class ArrowFunctionExpression extends Node {
 			}
 			code.remove(charIndex, this.body.start);
 
+			AwaitExpression.removeAsync(code, transforms, this.async, this.start);
 			super.transpile(code, transforms);
 
 			// wrap naked parameter
@@ -34,6 +36,7 @@ export default class ArrowFunctionExpression extends Node {
 				code.prependRight(this.start, 'function ');
 			}
 		} else {
+			AwaitExpression.removeAsync(code, transforms, this.async, this.start);
 			super.transpile(code, transforms);
 		}
 

diff --git a/src/program/types/AwaitExpression.js b/src/program/types/AwaitExpression.js
@@ -0,0 +1,20 @@
+import Node from '../Node.js';
+
+const noop = () => {};
+
+export default class AwaitExpression extends Node {
+	static removeAsync(code, transforms, async, start, callback = noop) {
+		if (transforms.asyncAwait && async) {
+			code.remove(start, start + 6);
+			callback();
+		}
+	}
+
+	transpile (code, transforms) {
+		AwaitExpression.removeAsync(code, transforms, true, this.start, () => {
+			code.insertLeft(this.argument.start, 'return ');
+		});
+
+		super.transpile(code, transforms);
+	}
+}
diff --git a/src/program/types/FunctionDeclaration.js b/src/program/types/FunctionDeclaration.js
@@ -1,6 +1,7 @@
 import Node from '../Node.js';
 import CompileError from '../../utils/CompileError.js';
 import removeTrailingComma from '../../utils/removeTrailingComma.js';
+import AwaitExpression from './AwaitExpression';
 
 export default class FunctionDeclaration extends Node {
 	initialise(transforms) {
@@ -17,6 +18,7 @@ export default class FunctionDeclaration extends Node {
 	}
 
 	transpile(code, transforms) {
+		AwaitExpression.removeAsync(code, transforms, this.async, this.start);
 		super.transpile(code, transforms);
 		if (transforms.trailingFunctionCommas && this.params.length) {
 			removeTrailingComma(code, this.params[this.params.length - 1].end);

diff --git a/src/program/types/index.js b/src/program/types/index.js
@@ -1,6 +1,7 @@
 import ArrayExpression from './ArrayExpression.js';
 import ArrowFunctionExpression from './ArrowFunctionExpression.js';
 import AssignmentExpression from './AssignmentExpression.js';
+import AwaitExpression from './AwaitExpression.js';
 import BinaryExpression from './BinaryExpression.js';
 import BreakStatement from './BreakStatement.js';
 import CallExpression from './CallExpression.js';
@@ -50,6 +51,7 @@ export default {
 	ArrayExpression,
 	ArrowFunctionExpression,
 	AssignmentExpression,
+	AwaitExpression,
 	BinaryExpression,
 	BreakStatement,
 	CallExpression,

diff --git a/src/support.js b/src/support.js
@@ -1,74 +1,75 @@
 export const matrix = {
 	chrome: {
-		    48: 0b01001010100011001111,
-		    49: 0b01001111100111111111,
-		    50: 0b01011111100111111111,
-		    51: 0b01011111100111111111,
-		    52: 0b01111111100111111111,
-		    53: 0b01111111100111111111,
-		    54: 0b01111111100111111111,
-		    55: 0b01111111100111111111,
-		    56: 0b01111111100111111111,
-		    57: 0b01111111100111111111,
-		    58: 0b11111111100111111111,
-		    59: 0b11111111100111111111,
-		    60: 0b11111111100111111111,
-		    61: 0b11111111100111111111,
-		    62: 0b11111111100111111111,
-		    63: 0b11111111100111111111
+		    48: 0b010010101000110011101,
+		    49: 0b010011111001111111101,
+		    50: 0b010111111001111111101,
+		    51: 0b010111111001111111101,
+		    52: 0b011111111001111111101,
+		    53: 0b011111111001111111101,
+		    54: 0b011111111001111111101,
+		    55: 0b011111111001111111111,
+		    56: 0b011111111001111111111,
+		    57: 0b011111111001111111111,
+		    58: 0b111111111001111111111,
+		    59: 0b111111111001111111111,
+		    60: 0b111111111001111111111,
+		    61: 0b111111111001111111111,
+		    62: 0b111111111001111111111,
+		    63: 0b111111111001111111111
 	},
 	firefox: {
-		    43: 0b01001110100011011101,
-		    44: 0b01001110100111011101,
-		    45: 0b01001110100111011111,
-		    46: 0b01011110100111011111,
-		    47: 0b01011110100111111111,
-		    48: 0b01011110100111111111,
-		    49: 0b01011110100111111111,
-		    50: 0b01011110100111111111,
-		    51: 0b01011110100111111111,
-		    52: 0b11111111100111111111,
-		    53: 0b11111111100111111111,
-		    54: 0b11111111100111111111,
-		    55: 0b11111111100111111111,
-		    56: 0b11111111100111111111,
-		    57: 0b11111111100111111111,
-		    58: 0b11111111100111111111
+		    43: 0b010011101000110111001,
+		    44: 0b010011101001110111001,
+		    45: 0b010011101001110111101,
+		    46: 0b010111101001110111101,
+		    47: 0b010111101001111111101,
+		    48: 0b010111101001111111101,
+		    49: 0b010111101001111111101,
+		    50: 0b010111101001111111101,
+		    51: 0b010111101001111111101,
+		    52: 0b111111111001111111111,
+		    53: 0b111111111001111111111,
+		    54: 0b111111111001111111111,
+		    55: 0b111111111001111111111,
+		    56: 0b111111111001111111111,
+		    57: 0b111111111001111111111,
+		    58: 0b111111111001111111111
 	},
 	safari: {
-		     8: 0b01000000000000000100,
-		     9: 0b01001001100001101110,
-		    10: 0b11011111100111111111,
-		'10.1': 0b11111111100111111111,
-		    11: 0b11111111100111111111
+		     8: 0b010000000000000001000,
+		     9: 0b010010011000011011100,
+		    10: 0b110111111001111111101,
+		'10.1': 0b111111111001111111111,
+		    11: 0b111111111001111111111
 	},
 	ie: {
-		     8: 0b00000000000000000000,
-		     9: 0b01000000000000000000,
-		    10: 0b01000000000000000000,
-		    11: 0b01000000000100000000
+		     8: 0b000000000000000000000,
+		     9: 0b010000000000000000000,
+		    10: 0b010000000000000000000,
+		    11: 0b010000000001000000000
 	},
 	edge: {
-		    12: 0b01001010100101001101,
-		    13: 0b01011110100111001111,
-		    14: 0b11111110100111111111,
-		    15: 0b11111110100111111111,
-		    16: 0b11111110100111111111
+		    12: 0b010010101001010011001,
+		    13: 0b010111101001110011101,
+		    14: 0b111111101001111111101,
+		    15: 0b111111101001111111111,
+		    16: 0b111111101001111111111
 	},
 	node: {
-		'0.10': 0b01000000000000000000,
-		'0.12': 0b01000000000001000000,
-		     4: 0b01001000100011001111,
-		     5: 0b01001000100011001111,
-		     6: 0b01011111100111111111,
-		     8: 0b11111111100111111111,
-		 '8.3': 0b11111111100111111111,
-		 '8.7': 0b11111111100111111111
+		'0.10': 0b010000000000000000000,
+		'0.12': 0b010000000000010000000,
+		     4: 0b010010001000110011101,
+		     5: 0b010010001000110011101,
+		     6: 0b010111111001111111101,
+		     8: 0b111111111001111111111,
+		 '8.3': 0b111111111001111111111,
+		 '8.7': 0b111111111001111111111
 	}
 };
 
 export const features = [
 	'arrow',
+	'asyncAwait',
 	'classes',
 	'computedProperty',
 	'conciseMethodProperty',

diff --git a/test/samples/async-await.js b/test/samples/async-await.js
@@ -0,0 +1,25 @@
+module.exports = [
+	{
+		description: 'transpiles await arrow function call',
+		input: `async () => await a()`,
+		output: `!function() { return Promise.resolve().then(function() { return a() }); }`
+	},
+
+	{
+		description: 'transpiles await function call',
+		input: `async function f() { await a(); }`,
+		output: `function f() { return Promise.resolve().then(function() { return a(); }).then(function() {}) }`
+	},
+
+	{
+		description: 'transpiles await function call with return statement',
+		input: `async function f() { return await a(); }`,
+		output: `function f() { return Promise.resolve().then(function() { return a(); }) }`
+	},
+
+	{
+		description: 'transpiles await function call with more than one line of code',
+		input: `async function f() { await a(); thing(); await a2(); stuff(); await a3(); await a4(); }`,
+		output: `function f() { return Promise.resolve().then(function() { return a(); }) .then(function() { thing(); }) .then(function() { return a2(); }) .then(function() { stuff(); }) .then(function() { return a3(); }) .then(function() { return a4(); }).then(function() {}) }`
+	}
+];