1 |
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2 |
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3 | function id (e) { return e }
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4 | var prop = require('../util/prop')
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5 |
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6 | module.exports = function map (mapper) {
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7 | if(!mapper) return id
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8 | mapper = prop(mapper)
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9 | return function (read) {
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10 | return function (abort, cb) {
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11 | read(abort, function (end, data) {
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12 | try {
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13 | data = !end ? mapper(data) : null
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14 | } catch (err) {
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15 | return read(err, function () {
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16 | return cb(err)
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17 | })
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18 | }
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19 | cb(end, data)
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20 | })
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21 | }
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22 | }
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23 | }
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