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| 1 | +// copied from https://github.com/nodejs/node/blob/88799930794045795e8abac874730f9eba7e2300/lib/internal/repl/await.js |
| 2 | +'use strict'; |
| 3 | + |
| 4 | +const { |
| 5 | + ArrayFrom, |
| 6 | + ArrayPrototypeForEach, |
| 7 | + ArrayPrototypeIncludes, |
| 8 | + ArrayPrototypeJoin, |
| 9 | + ArrayPrototypePop, |
| 10 | + ArrayPrototypePush, |
| 11 | + FunctionPrototype, |
| 12 | + ObjectKeys, |
| 13 | + RegExpPrototypeSymbolReplace, |
| 14 | + StringPrototypeEndsWith, |
| 15 | + StringPrototypeIncludes, |
| 16 | + StringPrototypeIndexOf, |
| 17 | + StringPrototypeRepeat, |
| 18 | + StringPrototypeSplit, |
| 19 | + StringPrototypeStartsWith, |
| 20 | + SyntaxError, |
| 21 | +} = require('./node-primordials'); |
| 22 | + |
| 23 | +const parser = require('acorn').Parser; |
| 24 | +const walk = require('acorn-walk'); |
| 25 | +const { Recoverable } = require('repl'); |
| 26 | + |
| 27 | +function isTopLevelDeclaration(state) { |
| 28 | + return state.ancestors[state.ancestors.length - 2] === state.body; |
| 29 | +} |
| 30 | + |
| 31 | +const noop = FunctionPrototype; |
| 32 | +const visitorsWithoutAncestors = { |
| 33 | + ClassDeclaration(node, state, c) { |
| 34 | + if (isTopLevelDeclaration(state)) { |
| 35 | + state.prepend(node, `${node.id.name}=`); |
| 36 | + ArrayPrototypePush( |
| 37 | + state.hoistedDeclarationStatements, |
| 38 | + `let ${node.id.name}; ` |
| 39 | + ); |
| 40 | + } |
| 41 | + |
| 42 | + walk.base.ClassDeclaration(node, state, c); |
| 43 | + }, |
| 44 | + ForOfStatement(node, state, c) { |
| 45 | + if (node.await === true) { |
| 46 | + state.containsAwait = true; |
| 47 | + } |
| 48 | + walk.base.ForOfStatement(node, state, c); |
| 49 | + }, |
| 50 | + FunctionDeclaration(node, state, c) { |
| 51 | + state.prepend(node, `${node.id.name}=`); |
| 52 | + ArrayPrototypePush( |
| 53 | + state.hoistedDeclarationStatements, |
| 54 | + `var ${node.id.name}; ` |
| 55 | + ); |
| 56 | + }, |
| 57 | + FunctionExpression: noop, |
| 58 | + ArrowFunctionExpression: noop, |
| 59 | + MethodDefinition: noop, |
| 60 | + AwaitExpression(node, state, c) { |
| 61 | + state.containsAwait = true; |
| 62 | + walk.base.AwaitExpression(node, state, c); |
| 63 | + }, |
| 64 | + ReturnStatement(node, state, c) { |
| 65 | + state.containsReturn = true; |
| 66 | + walk.base.ReturnStatement(node, state, c); |
| 67 | + }, |
| 68 | + VariableDeclaration(node, state, c) { |
| 69 | + const variableKind = node.kind; |
| 70 | + const isIterableForDeclaration = ArrayPrototypeIncludes( |
| 71 | + ['ForOfStatement', 'ForInStatement'], |
| 72 | + state.ancestors[state.ancestors.length - 2].type |
| 73 | + ); |
| 74 | + |
| 75 | + if (variableKind === 'var' || isTopLevelDeclaration(state)) { |
| 76 | + state.replace( |
| 77 | + node.start, |
| 78 | + node.start + variableKind.length + (isIterableForDeclaration ? 1 : 0), |
| 79 | + variableKind === 'var' && isIterableForDeclaration ? |
| 80 | + '' : |
| 81 | + 'void' + (node.declarations.length === 1 ? '' : ' (') |
| 82 | + ); |
| 83 | + |
| 84 | + if (!isIterableForDeclaration) { |
| 85 | + ArrayPrototypeForEach(node.declarations, (decl) => { |
| 86 | + state.prepend(decl, '('); |
| 87 | + state.append(decl, decl.init ? ')' : '=undefined)'); |
| 88 | + }); |
| 89 | + |
| 90 | + if (node.declarations.length !== 1) { |
| 91 | + state.append(node.declarations[node.declarations.length - 1], ')'); |
| 92 | + } |
| 93 | + } |
| 94 | + |
| 95 | + const variableIdentifiersToHoist = [ |
| 96 | + ['var', []], |
| 97 | + ['let', []], |
| 98 | + ]; |
| 99 | + function registerVariableDeclarationIdentifiers(node) { |
| 100 | + switch (node.type) { |
| 101 | + case 'Identifier': |
| 102 | + ArrayPrototypePush( |
| 103 | + variableIdentifiersToHoist[variableKind === 'var' ? 0 : 1][1], |
| 104 | + node.name |
| 105 | + ); |
| 106 | + break; |
| 107 | + case 'ObjectPattern': |
| 108 | + ArrayPrototypeForEach(node.properties, (property) => { |
| 109 | + registerVariableDeclarationIdentifiers(property.value); |
| 110 | + }); |
| 111 | + break; |
| 112 | + case 'ArrayPattern': |
| 113 | + ArrayPrototypeForEach(node.elements, (element) => { |
| 114 | + registerVariableDeclarationIdentifiers(element); |
| 115 | + }); |
| 116 | + break; |
| 117 | + } |
| 118 | + } |
| 119 | + |
| 120 | + ArrayPrototypeForEach(node.declarations, (decl) => { |
| 121 | + registerVariableDeclarationIdentifiers(decl.id); |
| 122 | + }); |
| 123 | + |
| 124 | + ArrayPrototypeForEach( |
| 125 | + variableIdentifiersToHoist, |
| 126 | + ({ 0: kind, 1: identifiers }) => { |
| 127 | + if (identifiers.length > 0) { |
| 128 | + ArrayPrototypePush( |
| 129 | + state.hoistedDeclarationStatements, |
| 130 | + `${kind} ${ArrayPrototypeJoin(identifiers, ', ')}; ` |
| 131 | + ); |
| 132 | + } |
| 133 | + } |
| 134 | + ); |
| 135 | + } |
| 136 | + |
| 137 | + walk.base.VariableDeclaration(node, state, c); |
| 138 | + } |
| 139 | +}; |
| 140 | + |
| 141 | +const visitors = {}; |
| 142 | +for (const nodeType of ObjectKeys(walk.base)) { |
| 143 | + const callback = visitorsWithoutAncestors[nodeType] || walk.base[nodeType]; |
| 144 | + visitors[nodeType] = (node, state, c) => { |
| 145 | + const isNew = node !== state.ancestors[state.ancestors.length - 1]; |
| 146 | + if (isNew) { |
| 147 | + ArrayPrototypePush(state.ancestors, node); |
| 148 | + } |
| 149 | + callback(node, state, c); |
| 150 | + if (isNew) { |
| 151 | + ArrayPrototypePop(state.ancestors); |
| 152 | + } |
| 153 | + }; |
| 154 | +} |
| 155 | + |
| 156 | +function processTopLevelAwait(src) { |
| 157 | + const wrapPrefix = '(async () => { '; |
| 158 | + const wrapped = `${wrapPrefix}${src} })()`; |
| 159 | + const wrappedArray = ArrayFrom(wrapped); |
| 160 | + let root; |
| 161 | + try { |
| 162 | + root = parser.parse(wrapped, { ecmaVersion: 'latest' }); |
| 163 | + } catch (e) { |
| 164 | + if (StringPrototypeStartsWith(e.message, 'Unterminated ')) |
| 165 | + throw new Recoverable(e); |
| 166 | + // If the parse error is before the first "await", then use the execution |
| 167 | + // error. Otherwise we must emit this parse error, making it look like a |
| 168 | + // proper syntax error. |
| 169 | + const awaitPos = StringPrototypeIndexOf(src, 'await'); |
| 170 | + const errPos = e.pos - wrapPrefix.length; |
| 171 | + if (awaitPos > errPos) |
| 172 | + return null; |
| 173 | + // Convert keyword parse errors on await into their original errors when |
| 174 | + // possible. |
| 175 | + if (errPos === awaitPos + 6 && |
| 176 | + StringPrototypeIncludes(e.message, 'Expecting Unicode escape sequence')) |
| 177 | + return null; |
| 178 | + if (errPos === awaitPos + 7 && |
| 179 | + StringPrototypeIncludes(e.message, 'Unexpected token')) |
| 180 | + return null; |
| 181 | + const line = e.loc.line; |
| 182 | + const column = line === 1 ? e.loc.column - wrapPrefix.length : e.loc.column; |
| 183 | + let message = '\n' + StringPrototypeSplit(src, '\n')[line - 1] + '\n' + |
| 184 | + StringPrototypeRepeat(' ', column) + |
| 185 | + '^\n\n' + RegExpPrototypeSymbolReplace(/ \([^)]+\)/, e.message, ''); |
| 186 | + // V8 unexpected token errors include the token string. |
| 187 | + if (StringPrototypeEndsWith(message, 'Unexpected token')) |
| 188 | + message += " '" + |
| 189 | + // Wrapper end may cause acorn to report error position after the source |
| 190 | + ((src.length - 1) >= (e.pos - wrapPrefix.length) |
| 191 | + ? src[e.pos - wrapPrefix.length] |
| 192 | + : src[src.length - 1]) + |
| 193 | + "'"; |
| 194 | + // eslint-disable-next-line no-restricted-syntax |
| 195 | + throw new SyntaxError(message); |
| 196 | + } |
| 197 | + const body = root.body[0].expression.callee.body; |
| 198 | + const state = { |
| 199 | + body, |
| 200 | + ancestors: [], |
| 201 | + hoistedDeclarationStatements: [], |
| 202 | + replace(from, to, str) { |
| 203 | + for (let i = from; i < to; i++) { |
| 204 | + wrappedArray[i] = ''; |
| 205 | + } |
| 206 | + if (from === to) str += wrappedArray[from]; |
| 207 | + wrappedArray[from] = str; |
| 208 | + }, |
| 209 | + prepend(node, str) { |
| 210 | + wrappedArray[node.start] = str + wrappedArray[node.start]; |
| 211 | + }, |
| 212 | + append(node, str) { |
| 213 | + wrappedArray[node.end - 1] += str; |
| 214 | + }, |
| 215 | + containsAwait: false, |
| 216 | + containsReturn: false |
| 217 | + }; |
| 218 | + |
| 219 | + walk.recursive(body, state, visitors); |
| 220 | + |
| 221 | + // Do not transform if |
| 222 | + // 1. False alarm: there isn't actually an await expression. |
| 223 | + // 2. There is a top-level return, which is not allowed. |
| 224 | + if (!state.containsAwait || state.containsReturn) { |
| 225 | + return null; |
| 226 | + } |
| 227 | + |
| 228 | + const last = body.body[body.body.length - 1]; |
| 229 | + if (last.type === 'ExpressionStatement') { |
| 230 | + // For an expression statement of the form |
| 231 | + // ( expr ) ; |
| 232 | + // ^^^^^^^^^^ // last |
| 233 | + // ^^^^ // last.expression |
| 234 | + // |
| 235 | + // We do not want the left parenthesis before the `return` keyword; |
| 236 | + // therefore we prepend the `return (` to `last`. |
| 237 | + // |
| 238 | + // On the other hand, we do not want the right parenthesis after the |
| 239 | + // semicolon. Since there can only be more right parentheses between |
| 240 | + // last.expression.end and the semicolon, appending one more to |
| 241 | + // last.expression should be fine. |
| 242 | + state.prepend(last, 'return ('); |
| 243 | + state.append(last.expression, ')'); |
| 244 | + } |
| 245 | + |
| 246 | + return ( |
| 247 | + ArrayPrototypeJoin(state.hoistedDeclarationStatements, '') + |
| 248 | + ArrayPrototypeJoin(wrappedArray, '') |
| 249 | + ); |
| 250 | +} |
| 251 | + |
| 252 | +module.exports = { |
| 253 | + processTopLevelAwait |
| 254 | +}; |
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