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Merge pull request #3365 from jridgewell/replace-implicit-arrow-with-block

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Replace arrow expression body with block statement
This commit is contained in:
Henry Zhu
2016-02-25 22:02:31 -05:00
parent bf05b1b3bc de1431e8c6
commit b8cdd6e28c
3 changed files with 166 additions and 6 deletions
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24
packages/babel-traverse/src/path/introspection.js
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@@ -116,7 +116,7 @@ export function isNodeType(type: string): boolean {
}
/**
* This checks whether or now we're in one of the following positions:
* This checks whether or not we're in one of the following positions:
*
* for (KEY in right);
* for (KEY;;);
@@ -129,6 +129,28 @@ export function canHaveVariableDeclarationOrExpression() {
return (this.key === "init" || this.key === "left") && this.parentPath.isFor();
}
/**
* This checks whether we are swapping an arrow function's body between an
* expression and a block statement (or vice versa).
*
* This is because arrow functions may implicitly return an expression, which
* is the same as containing a block statement.
*/
export function canSwapBetweenExpressionAndStatement(replacement) {
if (this.key !== "body" || !this.parentPath.isArrowFunctionExpression()) {
return false;
}
if (this.isExpression()) {
return t.isBlockStatement(replacement);
} else if (this.isBlockStatement()) {
return t.isExpression(replacement);
}
return false;
}
/**
* Check whether the current path references a completion record
*/

14
packages/babel-traverse/src/path/replacement.js
View File

@@ -121,14 +121,18 @@ export function replaceWith(replacement) {
throw new Error("Don't use `path.replaceWith()` with a source string, use `path.replaceWithSourceString()`");
}
// replacing a statement with an expression so wrap it in an expression statement
if (this.isNodeType("Statement") && t.isExpression(replacement) && !this.canHaveVariableDeclarationOrExpression()) {
replacement = t.expressionStatement(replacement);
if (this.isNodeType("Statement") && t.isExpression(replacement)) {
if (!this.canHaveVariableDeclarationOrExpression() && !this.canSwapBetweenExpressionAndStatement(replacement)) {
// replacing a statement with an expression so wrap it in an expression statement
replacement = t.expressionStatement(replacement);
}
}
// replacing an expression with a statement so let's explode it
if (this.isNodeType("Expression") && t.isStatement(replacement)) {
return this.replaceExpressionWithStatements([replacement]);
if (!this.canHaveVariableDeclarationOrExpression() && !this.canSwapBetweenExpressionAndStatement(replacement)) {
// replacing an expression with a statement so let's explode it
return this.replaceExpressionWithStatements([replacement]);
}
}
let oldNode = this.node;