/
ExportDefaultDeclaration.ts
164 lines (151 loc) · 5.02 KB
/
ExportDefaultDeclaration.ts
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import MagicString from 'magic-string';
import { BLANK } from '../../utils/blank';
import {
findFirstOccurrenceOutsideComment,
NodeRenderOptions,
RenderOptions
} from '../../utils/renderHelpers';
import { treeshakeNode } from '../../utils/treeshakeNode';
import ModuleScope from '../scopes/ModuleScope';
import ExportDefaultVariable from '../variables/ExportDefaultVariable';
import ClassDeclaration from './ClassDeclaration';
import FunctionDeclaration from './FunctionDeclaration';
import Identifier from './Identifier';
import * as NodeType from './NodeType';
import { ExpressionNode, IncludeChildren, NodeBase } from './shared/Node';
const WHITESPACE = /\s/;
// The header ends at the first non-white-space after "default"
function getDeclarationStart(code: string, start = 0) {
start = findFirstOccurrenceOutsideComment(code, 'default', start) + 7;
while (WHITESPACE.test(code[start])) start++;
return start;
}
function getIdInsertPosition(code: string, declarationKeyword: string, start = 0) {
const declarationEnd =
findFirstOccurrenceOutsideComment(code, declarationKeyword, start) + declarationKeyword.length;
code = code.slice(declarationEnd, findFirstOccurrenceOutsideComment(code, '{', declarationEnd));
const generatorStarPos = findFirstOccurrenceOutsideComment(code, '*');
if (generatorStarPos === -1) {
return declarationEnd;
}
return declarationEnd + generatorStarPos + 1;
}
export default class ExportDefaultDeclaration extends NodeBase {
declaration!: FunctionDeclaration | ClassDeclaration | ExpressionNode;
needsBoundaries!: true;
scope!: ModuleScope;
type!: NodeType.tExportDefaultDeclaration;
variable!: ExportDefaultVariable;
private declarationName: string | undefined;
include(includeChildrenRecursively: IncludeChildren) {
super.include(includeChildrenRecursively);
if (includeChildrenRecursively) {
this.context.includeVariable(this.variable);
}
}
initialise() {
const declaration = this.declaration as FunctionDeclaration | ClassDeclaration;
this.declarationName =
(declaration.id && declaration.id.name) || (this.declaration as Identifier).name;
this.variable = this.scope.addExportDefaultDeclaration(
this.declarationName || this.context.getModuleName(),
this,
this.context
);
this.context.addExport(this);
}
render(code: MagicString, options: RenderOptions, { start, end }: NodeRenderOptions = BLANK) {
const declarationStart = getDeclarationStart(code.original, this.start);
if (this.declaration instanceof FunctionDeclaration) {
this.renderNamedDeclaration(
code,
declarationStart,
'function',
this.declaration.id === null,
options
);
} else if (this.declaration instanceof ClassDeclaration) {
this.renderNamedDeclaration(
code,
declarationStart,
'class',
this.declaration.id === null,
options
);
} else if (this.variable.getOriginalVariable() !== this.variable) {
// Remove altogether to prevent re-declaring the same variable
if (options.format === 'system' && this.variable.exportName) {
code.overwrite(
start as number,
end as number,
`exports('${this.variable.exportName}', ${this.variable.getName()});`
);
} else {
treeshakeNode(this, code, start as number, end as number);
}
return;
} else if (this.variable.included) {
this.renderVariableDeclaration(code, declarationStart, options);
} else {
code.remove(this.start, declarationStart);
this.declaration.render(code, options, {
isCalleeOfRenderedParent: false,
renderedParentType: NodeType.ExpressionStatement
});
if (code.original[this.end - 1] !== ';') {
code.appendLeft(this.end, ';');
}
return;
}
this.declaration.render(code, options);
}
private renderNamedDeclaration(
code: MagicString,
declarationStart: number,
declarationKeyword: string,
needsId: boolean,
options: RenderOptions
) {
const name = this.variable.getName();
// Remove `export default`
code.remove(this.start, declarationStart);
if (needsId) {
code.appendLeft(
getIdInsertPosition(code.original, declarationKeyword, declarationStart),
` ${name}`
);
}
if (
options.format === 'system' &&
this.declaration instanceof ClassDeclaration &&
this.variable.exportName
) {
code.appendLeft(this.end, ` exports('${this.variable.exportName}', ${name});`);
}
}
private renderVariableDeclaration(
code: MagicString,
declarationStart: number,
options: RenderOptions
) {
const systemBinding =
options.format === 'system' && this.variable.exportName
? `exports('${this.variable.exportName}', `
: '';
code.overwrite(
this.start,
declarationStart,
`${options.varOrConst} ${this.variable.getName()} = ${systemBinding}`
);
const hasTrailingSemicolon = code.original.charCodeAt(this.end - 1) === 59; /*";"*/
if (systemBinding) {
code.appendRight(
hasTrailingSemicolon ? this.end - 1 : this.end,
')' + (hasTrailingSemicolon ? '' : ';')
);
} else if (!hasTrailingSemicolon) {
code.appendLeft(this.end, ';');
}
}
}
ExportDefaultDeclaration.prototype.needsBoundaries = true;