All files / src/node-transformers/converting-transformers TemplateLiteralTransformer.ts

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
1x
1x
 
 
 
 
 
 
1x
1x
1x
 
 
 
 
 
 
1x
 
 
 
 
 
 
6262x
 
 
 
 
 
 
 
6x
 
 
 
 
 
 
6262x
 
664830x
4x
 
 
 
 
 
 
 
 
 
 
 
4x
 
4x
 
4x
9x
 
9x
 
9x
4x
 
 
5x
 
 
4x
14x
 
 
 
 
4x
 
 
 
1x
 
 
4x
3x
 
 
 
 
 
3x
1x
 
 
 
 
 
1x
 
 
 
import { injectable, inject } from 'inversify';
import { ServiceIdentifiers } from '../../container/ServiceIdentifiers';
 
import * as ESTree from 'estree';
 
import { IOptions } from '../../interfaces/options/IOptions';
import { IVisitor } from '../../interfaces/IVisitor';
 
import { AbstractNodeTransformer } from '../AbstractNodeTransformer';
import { Node } from '../../node/Node';
import { Nodes } from '../../node/Nodes';
 
/**
 * Transform ES2015 template literals to ES5
 * Thanks to Babel for algorithm
 */
@injectable()
export class TemplateLiteralTransformer extends AbstractNodeTransformer {
    /**
     * @param options
     */
    constructor (
        @inject(ServiceIdentifiers.IOptions) options: IOptions
    ) {
        super(options);
    }
 
    /**
     * @param node
     * @return {boolean}
     */
    private static isLiteralNodeWithStringValue (node: ESTree.Node): boolean {
        return node && Node.isLiteralNode(node) && typeof node.value === 'string';
    }
 
    /**
     * @return {IVisitor}
     */
    public getVisitor (): IVisitor {
        return {
            enter: (node: ESTree.Node, parentNode: ESTree.Node) => {
                if (Node.isTemplateLiteralNode(node)) {
                    return this.transformNode(node, parentNode);
                }
            }
        };
    }
 
    /**
     * @param templateLiteralNode
     * @param parentNode
     * @returns {ESTree.Node}
     */
    public transformNode (templateLiteralNode: ESTree.TemplateLiteral, parentNode: ESTree.Node): ESTree.Node {
        const templateLiteralExpressions: ESTree.Expression[] = templateLiteralNode.expressions;
 
        let nodes: (ESTree.Literal | ESTree.Expression)[] = [];
 
        templateLiteralNode.quasis.forEach((templateElement: ESTree.TemplateElement) => {
            nodes.push(Nodes.getLiteralNode(templateElement.value.cooked));
 
            const expression: ESTree.Expression | undefined = templateLiteralExpressions.shift();
 
            if (!expression) {
                return;
            }
 
            nodes.push(expression);
        });
 
        nodes = nodes.filter((node: ESTree.Literal | ESTree.Expression) => {
            return !(Node.isLiteralNode(node) && node.value === '');
        });
 
        // since `+` is left-to-right associative
        // ensure the first node is a string if first/second isn't
        if (
            !TemplateLiteralTransformer.isLiteralNodeWithStringValue(nodes[0]) &&
            !TemplateLiteralTransformer.isLiteralNodeWithStringValue(nodes[1])
        ) {
            nodes.unshift(Nodes.getLiteralNode(''));
        }
 
        if (nodes.length > 1) {
            let root: ESTree.BinaryExpression = Nodes.getBinaryExpressionNode(
                '+',
                <ESTree.Literal>nodes.shift(),
                <ESTree.Expression>nodes.shift()
            );
 
            nodes.forEach((node: ESTree.Literal | ESTree.Expression) => {
                root = Nodes.getBinaryExpressionNode('+', root, <ESTree.Literal | ESTree.Expression>node);
            });
 
            return root;
        }
 
        return nodes[0];
    }
}