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'use strict'
const vm = require('vm')
const context = vm.createContext()
function test (code) {
try {
return vm.runInContext(`(function () {
'use strict'
${code}
})()`, context) === true
} catch (err) {
return false
}
}
const support = {}
// Tests from <https://github.com/kangax/compat-table/blob/c0a3b882b27e4e9f4ef449a1c985ee7857326b94/data-es6.js#L12733:L13115>.
support.functionStatements = test(`
function foo(){};
return foo.name === 'foo' &&
(function(){}).name === '';
`)
support.functionExpressions = test(`
return (function foo(){}).name === 'foo' &&
(function(){}).name === '';
`)
support.newFunction = test(`
return (new Function).name === "anonymous";
`)
support.boundFunctions = test(`
function foo() {};
return foo.bind({}).name === "bound foo" &&
(function(){}).bind({}).name === "bound ";
`)
support.functionVariables = test(`
var foo = function() {};
var bar = function baz() {};
return foo.name === "foo" && bar.name === "baz";
`)
support.functionObjectMethods = test(`
var o = { foo: function(){}, bar: function baz(){}};
o.qux = function(){};
return o.foo.name === "foo" &&
o.bar.name === "baz" &&
o.qux.name === "";
`)
support.accessorProperties = test(`
var o = { get foo(){}, set foo(x){} };
var descriptor = Object.getOwnPropertyDescriptor(o, "foo");
return descriptor.get.name === "get foo" &&
descriptor.set.name === "set foo";
`)
support.shorthandMethods = test(`
var o = { foo(){} };
return o.foo.name === "foo"
`)
support.symbolKeyedMethods = test(`
var sym1 = Symbol("foo");
var sym2 = Symbol();
var o = {
[sym1]: function(){},
[sym2]: function(){}
};
return o[sym1].name === "[foo]" &&
o[sym2].name === "";
`)
support.classStatements = test(`
class foo {};
class bar { static name() {} };
return foo.name === "foo" &&
typeof bar.name === "function";
`)
support.classExpressions = test(`
return class foo {}.name === "foo" &&
typeof class bar { static name() {} }.name === "function";
`)
support.classVariables = test(`
var foo = class {};
var bar = class baz {};
var qux = class { static name() {} };
return foo.name === "foo" &&
bar.name === "baz" &&
typeof qux.name === "function";
`)
support.classObjectMethods = test(`
var o = { foo: class {}, bar: class baz {}};
o.qux = class {};
return o.foo.name === "foo" &&
o.bar.name === "baz" &&
o.qux.name === "";
`)
support.classPrototypeMethods = test(`
class C { foo(){} };
return (new C).foo.name === "foo";
`)
support.classStaticMethods = test(`
class C { static foo(){} };
return C.foo.name === "foo";
`)
exports.support = Object.freeze(support)
const hasFullSupport =
support.functionStatements &&
support.functionExpressions &&
support.newFunction &&
support.boundFunctions &&
support.functionVariables &&
support.functionObjectMethods &&
support.accessorProperties &&
support.shorthandMethods &&
support.symbolKeyedMethods &&
support.classStatements &&
support.classExpressions &&
support.classVariables &&
support.classObjectMethods &&
support.classPrototypeMethods &&
support.classStaticMethods
exports.hasFullSupport = hasFullSupport
const bitFlags = [
'functionStatements',
'functionExpressions',
'newFunction',
'boundFunctions',
'functionVariables',
'functionObjectMethods',
'accessorProperties',
'shorthandMethods',
'symbolKeyedMethods',
'classStatements',
'classExpressions',
'classVariables',
'classObjectMethods',
'classPrototypeMethods',
'classStaticMethods'
// Add new flags at the end. Reordering flags is a breaking change.
].reduce((acc, key, index) => {
return support[key] === true
? acc + (1 << index)
: acc
}, 0b0)
exports.bitFlags = bitFlags
exports.isSubsetOf = otherFlags => (bitFlags & otherFlags) === bitFlags
exports.isSupersetOf = otherFlags => (bitFlags & otherFlags) === otherFlags
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