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[WIP] feat: new AST for microsyntax #277

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[WIP] feat: new AST for microsyntax #277

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f8f3a68
Add tests
fisker Nov 14, 2023
43949eb
Update
fisker Nov 14, 2023
91f256b
Test
fisker Nov 14, 2023
64dcfad
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fisker Nov 14, 2023
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2 changes: 1 addition & 1 deletion src/parser.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -66,7 +66,7 @@ function parseTemplateBindings(text: string) {
const parser = createParser();
const { templateBindings: expressions, errors } =
parser.parseTemplateBindings(
NG_PARSE_TEMPLATE_BINDINGS_FAKE_PREFIX,
'',
text,
NG_PARSE_FAKE_LOCATION,
NG_PARSE_FAKE_ABSOLUTE_OFFSET,
Expand Down
307 changes: 180 additions & 127 deletions src/transform-microsyntax.ts
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
import type * as ng from '@angular/compiler';
import * as ng from '@angular/compiler';
import type * as b from '@babel/types';
import {
ExpressionBinding as NGExpressionBinding,
VariableBinding as NGVariableBinding,
Expand All @@ -7,14 +8,11 @@ import { type Context } from './context.js';
import transformNode from './transform-node.js';
import type {
NGMicrosyntax,
NGMicrosyntaxAs,
NGMicrosyntaxExpression,
NGMicrosyntaxKey,
NGMicrosyntaxAsExpression,
NGMicrosyntaxKeyedExpression,
NGMicrosyntaxLet,
NGMicrosyntaxNode,
NGNode,
RawNGSpan,
NGMicrosyntaxOfExpression,
} from './types.js';
import { NG_PARSE_TEMPLATE_BINDINGS_FAKE_PREFIX } from './parser.js';
import { toLowerCamelCase, transformSpan, createNode } from './utils.js';
Expand Down Expand Up @@ -92,8 +90,91 @@ function transformTemplateBindings({
}): NGMicrosyntax {
rawTemplateBindings.forEach(fixTemplateBindingSpan);

function transformVariableBinding(variableBinding: ng.VariableBinding) {
const { key, sourceSpan } = variableBinding;
const startsWithLet = /^let\s$/.test(
context.text.slice(sourceSpan.start, sourceSpan.start + 4),
);
if (startsWithLet) {
const { value } = variableBinding;
const id = _c<b.Identifier>({
type: 'Identifier',
name: key.source,
...key.span,
});
const init = value
? _c<b.Identifier>({
type: 'Identifier',
name: value.source,
...value.span,
})
: null;
return _c<b.VariableDeclaration>({
type: 'VariableDeclaration',
kind: 'let',
declarations: [
_c<b.VariableDeclarator>({
type: 'VariableDeclarator',
id,
init,
...sourceSpan,
}),
],
...sourceSpan,
});
} else {
const value = getAsVariableBindingValue(variableBinding, context);
return _c<NGMicrosyntaxAsExpression>({
type: 'NGMicrosyntaxAsExpression',
expression: _c<b.Identifier>({
type: 'Identifier',
name: value!.source,
...value!.span,
}),
alias: _c<b.Identifier>({
type: 'Identifier',
name: key.source,
...key.span,
}),
start: value!.span.start,
end: key.span.end,
});
}
}

function transformExpressionBinding(expressionBinding: ng.ExpressionBinding) {
const { key, value } = expressionBinding;

if (!value) {
return transformTemplateBindingIdentifier(key);
}

const hasKey = key.source !== '';

if (hasKey) {
return _c<NGMicrosyntaxKeyedExpression>({
type: 'NGMicrosyntaxKeyedExpression',
key: transformTemplateBindingIdentifier(key),
expression: _t(value),
...expressionBinding.sourceSpan,
});
}

return _t<NGNode>(value);
}

function transformTemplateBinding(templateBinding: ng.TemplateBinding) {
if (isExpressionBinding(templateBinding)) {
return transformExpressionBinding(templateBinding);
}
if (isVariableBinding(templateBinding)) {
return transformVariableBinding(templateBinding);
}

throw new Error('Unexpected node');
}

const [firstTemplateBinding] = rawTemplateBindings;
const { key: prefix } = firstTemplateBinding;
const templateBindings =
context.text
.slice(
Expand All @@ -106,138 +187,100 @@ function transformTemplateBindings({

const body: NGMicrosyntax['body'] = [];

let lastTemplateBinding: ng.TemplateBinding | null = null;
function isOfExpression(node: ng.TemplateBinding) {
return (
isExpressionBinding(node) &&
node.key.source === 'Of' &&
node.value instanceof ng.ASTWithSource &&
context.text
.slice(node.key.span.end, node.value.sourceSpan.start)
.trim() === ''
);
}

function transformOfExpression(
first: ng.TemplateBinding,
second: ng.ExpressionBinding,
) {
const left = transformTemplateBinding(
first,
) as NGMicrosyntaxOfExpression['left'];
const right = _t(second.value!) as NGMicrosyntaxOfExpression['right'];

return _c<NGMicrosyntaxOfExpression>({
type: 'NGMicrosyntaxOfExpression',
left,
right,
start: left.start,
end: left.end,
});
}

function isAsExpression(
first: ng.TemplateBinding,
second: ng.TemplateBinding,
) {
return (
isExpressionBinding(first) &&
first.key.source === '' &&
first.value instanceof ng.ASTWithSource &&
isVariableBinding(second) &&
context.text.slice(first.value.span.end, second.key.span.start).trim() ==
'as'
);
}

function transformAsExpression(
first: ng.ExpressionBinding,
second: ng.VariableBinding,
) {
return _c<NGMicrosyntaxAsExpression>({
type: 'NGMicrosyntaxAsExpression',
expression: _t(first.value as ng.ASTWithSource),
alias: _c<b.Identifier>({
type: 'Identifier',
name: second.key.source,
...second.key.span,
}),
start: first.sourceSpan.start,
end: second.sourceSpan.end,
});
}

for (let i = 0; i < templateBindings.length; i++) {
const templateBinding = templateBindings[i];
const nextTemplateBinding = templateBindings[i + 1];
if (isOfExpression(nextTemplateBinding)) {
const ofExpression = transformOfExpression(
templateBinding,
nextTemplateBinding as ng.ExpressionBinding,
);

if (
lastTemplateBinding &&
isExpressionBinding(lastTemplateBinding) &&
isVariableBinding(templateBinding) &&
templateBinding.value &&
templateBinding.value.source === lastTemplateBinding.key.source
) {
const alias = _c<NGMicrosyntaxKey>({
type: 'NGMicrosyntaxKey',
name: templateBinding.key.source,
...templateBinding.key.span,
});
const updateSpanEnd = <T extends NGNode>(node: T, end: number): T => ({
...node,
...transformSpan({ start: node.start!, end }, context.text),
});
const updateExpressionAlias = (expression: NGMicrosyntaxExpression) => ({
...updateSpanEnd(expression, alias.end),
alias,
});
body.push(ofExpression);
i++;
continue;
}

const lastNode = body.pop()!;
// istanbul ignore else
if (lastNode.type === 'NGMicrosyntaxExpression') {
body.push(updateExpressionAlias(lastNode));
} else if (lastNode.type === 'NGMicrosyntaxKeyedExpression') {
const expression = updateExpressionAlias(lastNode.expression);
body.push(updateSpanEnd({ ...lastNode, expression }, expression.end));
} else {
throw new Error(`Unexpected type ${lastNode.type}`);
}
} else {
body.push(transformTemplateBinding(templateBinding, i));
if (isAsExpression(templateBinding, nextTemplateBinding)) {
const asExpression = transformAsExpression(
templateBinding as ng.ExpressionBinding,
nextTemplateBinding as ng.VariableBinding,
);
body.push(asExpression);
i++;
continue;
}

lastTemplateBinding = templateBinding;
body.push(transformTemplateBinding(templateBinding));
}

return _c<NGMicrosyntax>({
type: 'NGMicrosyntax',
body,
...(body.length === 0
? rawTemplateBindings[0].sourceSpan
: { start: body[0].start, end: body.at(-1)!.end }),
start: 0,
end: context.text.length,
});

function transformTemplateBinding(
templateBinding: ng.TemplateBinding,
index: number,
): Exclude<NGMicrosyntaxNode, NGMicrosyntax> {
if (isExpressionBinding(templateBinding)) {
const { key, value } = templateBinding;
if (!value) {
return _c<NGMicrosyntaxKey>({
type: 'NGMicrosyntaxKey',
name: removePrefix(key.source),
...key.span,
});
} else if (index === 0) {
return _c<NGMicrosyntaxExpression>({
type: 'NGMicrosyntaxExpression',
expression: _t<NGNode>(value.ast),
alias: null,
...value.sourceSpan,
});
} else {
return _c<NGMicrosyntaxKeyedExpression>({
type: 'NGMicrosyntaxKeyedExpression',
key: _c<NGMicrosyntaxKey>({
type: 'NGMicrosyntaxKey',
name: removePrefix(key.source),
...key.span,
}),
expression: _c<NGMicrosyntaxExpression>({
type: 'NGMicrosyntaxExpression',
expression: _t<NGNode>(value.ast),
alias: null,
...value.sourceSpan,
}),
start: key.span.start,
end: value.sourceSpan.end,
});
}
} else {
const { key, sourceSpan } = templateBinding;
const startsWithLet = /^let\s$/.test(
context.text.slice(sourceSpan.start, sourceSpan.start + 4),
);
if (startsWithLet) {
const { value } = templateBinding;
return _c<NGMicrosyntaxLet>({
type: 'NGMicrosyntaxLet',
key: _c<NGMicrosyntaxKey>({
type: 'NGMicrosyntaxKey',
name: key.source,
...key.span,
}),
value: !value
? null
: _c<NGMicrosyntaxKey>({
type: 'NGMicrosyntaxKey',
name: value.source,
...value.span,
}),
start: sourceSpan.start,
end: value ? value.span.end : key.span.end,
});
} else {
const value = getAsVariableBindingValue(templateBinding, context);
return _c<NGMicrosyntaxAs>({
type: 'NGMicrosyntaxAs',
key: _c<NGMicrosyntaxKey>({
type: 'NGMicrosyntaxKey',
name: value!.source,
...value!.span,
}),
alias: _c<NGMicrosyntaxKey>({
type: 'NGMicrosyntaxKey',
name: key.source,
...key.span,
}),
start: value!.span.start,
end: key.span.end,
});
}
}
}

function _t<T extends NGNode>(node: ng.AST) {
return transformNode(node, context) as T;
}
Expand All @@ -250,7 +293,7 @@ function transformTemplateBindings({
}

function removePrefix(string: string) {
return toLowerCamelCase(string.slice(prefix.source.length));
return toLowerCamelCase(string);
}

function fixTemplateBindingSpan(templateBinding: ng.TemplateBinding) {
Expand All @@ -259,6 +302,16 @@ function transformTemplateBindings({
fixSpan(templateBinding.value.span, context.text);
}
}

function transformTemplateBindingIdentifier(
node: ng.TemplateBindingIdentifier,
) {
return _c<b.Identifier>({
type: 'Identifier',
name: node.source,
...node.span,
});
}
}

export { transformTemplateBindings };
6 changes: 5 additions & 1 deletion src/transform-node.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,9 @@ function transform(
): NGNode {
const type = getAngularNodeType(node);
switch (type) {
case 'ASTWithSource': {
return _t((node as ng.ASTWithSource).ast);
}
case 'Unary': {
const { operator, expr } = node as ng.Unary;
const argumentNode = _t<b.Expression>(expr);
Expand Down Expand Up @@ -405,7 +408,8 @@ function transform(
}
// istanbul ignore next
default:
throw new Error(`Unexpected node ${type}`);
console.log(node);
throw new Error(`Unexpected node`);
}

function _t<T extends NGNode>(n: ng.AST) {
Expand Down
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