Function matchYield

lib/assets/javascripts/JSXTransformer.js:5253–5255

()

    // use matchKeyword('yield', false) and matchKeyword('yield', true)
    // (i.e. matchContextualKeyword) appropriately.
    function matchYield() {
        return state.yieldAllowed && matchKeyword('yield', !strict);
    }

    function matchAsync() {
        var backtrackToken = lookahead, matches = false;